Principle and Practices of Animal Breeding || Boby Basnet

Principle and Practices of Animal Breeding
Boby Basnet/Assistant Professor
Ilam Community Agriculture Campus
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Syllabus
Unit Topic Lecture
1.Introduction: importance, scope and history of animal breeding; indigenous breeds and their economic values, animal genetic resources and
sustainable development.
4 hrs
2.Rare breeds of different species of animal and their characteristics; reasons for being endangered and strategies for conservation. 4 hrs
3.Genetic principles of animal breeding. 3 hrs
4.Variation: concept of variation, importance of variation, causes of variation. 2 hrs
5.Heredity: meaning and importance of heredity; heredity and environment; heritability, repeatability and their estimates. 3 hrs
6.Breeding system and selection: principles, basis, method and selection parameters; important economic traits of livestock and poultry;
breeding plan.
5 hrs
7.Mating system: inbreeding and out breeding. 2 hrs
8.Genetic resistance to diseases and parasites. 2 hrs
9.Transgenic animals and their production. 2 hrs
10.Animal biotechnology and recent advances in animal biotechnology. 3 hrs
Boby Basnet/Assistant Professor 2

1. Introduction: Importance, scope and history
of animal breeding; indigenous breeds and their
economic values, animal genetic resources and
sustainable development.
Boby Basnet/Assistant Professor
Animal Science
Boby Basnet/Assistant Professor 3

Terminology
Gene is the basic unit of heredity, which carries genetic information from parents to offspring or from generation to generation.
Alleles is an alternate form of a gene; two genes that occupy the same position and cover the same trait.
Locus a fixed location on a strand of DNA where a gene or one of its alleles is located.
Homozygous having identical genes (one from each parent) for a particular characteristic.
Heterozygous having two different genes for a particular characteristic.
Dominant: the trait that appears in the heterozygous condition and masked the effect of the other.
Recessive: the trait that is masked in the heterozygous condition.
Phenotype: the physical expression or appearance of an organism.
Genotype: genetic makeup or genetic composition of an organism.
Inbred line: Group of related individuals derived from inbreeding for several generations.
Line: a group of animals derived from the common male ancestors or the founder of the line.
Atavism: Reappearance of the character after it has not appeared for one or more generations.
Pleiotropy: The phenomenon of single gene affecting more than one trait. (alleles for pigmentation i.e skin color, hair color, eye).
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F1: First filial generation form from a given mating (i.e the hybrid), offspring from mating the F1
generation are the F2 etc
Monohybrid cross - cross involving a single pair of genes, or one trait.
Dihybrid cross- cross involving two pairs of gene or traits.
Selection: The differential rate of reproduction. Superior individuals are selected based on their
reproductive abilities.
Inbreeding: Mating between the closely related individuals
Heredity: The transmission of genetic or physical traits from the parents to their offspring.
Inbreeding depression: Lowered performance that arises after increased inbreeding.
Culling: Elimination from the herd of an animals that fail to short the standards set by a breeder for
stated characters.
Breeding value: The genetically determined properties of an individuals which are demonstrated by
the exhibition of particular performance and the capacity for transmitting these genetic properties to
the progeny generation.
Genetic engineering: Altering the genetic structure of an organism by adding foreign genes through
application of biotechnology.
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INTRODUCTION
Breeding refers to the process of producing plants or animals with the goal
of developing new or improved types. It involves selecting and mating
individuals with desirable traits to enhance specific characteristics.
Breeding can be applied to both plants and animals, and when focused on
animals, it is called animal breeding or livestock breeding.
Animal breeding is the application of scientific knowledge
and principles of genetics to improve animals for specific
purposes, such as higher productivity, disease resistance, or
adaptability.
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Aim/Objectives of Animal Breeding
1. Improved Growth Rate
➢Enhance the speed at which animals grow, ensuring faster maturity and market readiness.
2. Increased Production of Animal Products
➢Boost the production of milk, meat, eggs, wool, and other animal-derived products.
3. Improved Quality of Animals and Their Products
➢Enhance traits such as milk composition, meat tenderness, egg size, and wool texture.
4. Disease Resistance
➢Breed animals with greater resistance to diseases and parasites, reducing dependency on medication.
➢Breed animals for aesthetic qualities, sports (e.g., racing horses or dogs), or exhibition purposes.
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5. Increased Productive Lifespan
➢Extend the duration of productive years in animals to maximize returns over their
lifetime.
6. Higher Reproductive Rate
➢Increase fertility rates and reproductive efficiency to improve herd or flock sizes.
7. Conservation of Genetic Resources
➢Preserve the diversity of indigenous and endangered breeds for future use and
adaptability.
8. Development of New Breeds
➢Create new breeds with specialized traits suited for specific purposes or environments.
9. Scientific Research and Innovation
➢Apply genetics and biometrics to develop better breeding techniques and improve
livestock systems.
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Scope of Animal Breeding
Improving Genetic Traits: Focus on increasing productivity traits like
milk yield, growth rate, egg production, and wool quality. Development of
specialized breeds tailored to specific farming systems.
Enhancing Disease Resistance: Breeding for stronger immune systems
reduces dependency on antibiotics and ensures healthier animals. Helps in
combating emerging diseases and improving animal welfare.
Environmental Adaptation: Develops breeds that thrive in specific
climates or challenging environments (e.g., drought-resistant goats, heat-
tolerant cattle).Addresses climate change impacts on livestock systems.
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Enhancing Product Quality
Improves meat tenderness, milk fat/protein content, egg size, and
wool texture, catering to market demands.
Increasing Production Efficiency
Focuses on traits like feed conversion efficiency to reduce input
costs while increasing output (e.g., milk per kg of feed or faster
weight gain).
Conservation of Rare and Indigenous Breeds
Preserves endangered breeds and their genetic diversity, ensuring
valuable traits are not lost
Behavioral Traits for Management
Breeds animals with docile and manageable temperaments,
improving handling and reducing stress.
Reducing Environmental Impact
Reduces greenhouse gas emissions (e.g., methane in ruminants) and
other waste outputs through selective breeding.
Adaptation to Market Demands
Aligns breeding programs with emerging trends such as organic
farming, animal welfare standards, and niche markets.
Improving Human Health
Breeds animals with nutritional benefits, such as low-cholesterol
meat or high omega-3 fish, supporting healthier diets.
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Importance of Animal Breeding
Genetic Improvement
Selective breeding improves
desirable traits such as higher
milk yield in dairy cattle or
faster growth in chickens,
ensuring better productivity
and efficiency.
Disease Resistance
Breeding programs enhance
animals' resistance to diseases
and parasites, reducing the
need for medication. For
instance, chickens can be bred
for stronger immunity to
diseases like avian influenza.
Efficiency in Production
Improves resource utilization
by selecting animals with
better feed conversion ratios,
such as pigs that efficiently
convert feed into body weight,
leading to reduced production
costs.
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Adaptation to Environment: Breeding enables animals to thrive in specific environmental
conditions. For example, sheep in mountainous regions are bred for thicker wool to withstand
cold temperatures.
Reproductive Performance: Enhances traits such as fertility and litter size, boosting
productivity.
Temperament and Behavior: Selective breeding can improve behavioral traits, making
animals easier to manage or suited for specific roles. For example, calm and trainable dogs are
bred for service and therapy work.
Improved Product Quality Breeding: enhances the quality of animal products like meat,
milk, and eggs. For example, beef cattle can be bred for better marbling in meat, improving
flavor and tenderness.
Conservation of Rare Breeds: Breeding programs help conserve endangered breeds like
Lulu, Parkote, Gaddi ensuring genetic diversity for future needs.
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History
Early Efforts in Livestock Breeding
More than a thousand years ago, the Arabs bred horses based on detailed family histories. This
practice laid the groundwork for using pedigree information in animal selection. Systematic
breeding further developed during the 18th century, with Robert Bakewell (1725-1795,
England) widely regarded as the father of livestock selection. He introduced methodological
selection processes and focused on producing farm animals including cattle, sheep, and horses
with increased efficiency. Bakewell popularized pedigree breeding and used inbreeding
techniques to create herds with uniform superiority, leading to the development of relatively
true breeding strains. He also introduced concepts such as progeny testing, accurate breeding
records, and the principle of "breed the best to the best."
Boby Basnet/Assistant Professor
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History
Contributions of Key Scientists
1.Francis Galton (1822-1911): Introduced statistical methods to the study of heredity, earning recognition as
the founder of biometry.
2.William Bateson (1861-1926): First demonstrated the inheritance of qualitative traits in farm animals, further
advancing genetic understanding.
3.Hazel and Lush (1942): Developed the selection index, which opened new theoretical developments in
animal breeding. Lush is considered the father of the modern science of animal breeding.
Development of Herd Books
The first herd book, titled "An Introduction to the General Stud Book," was established in 1791 and recorded
the pedigrees of thoroughbred horses. Subsequent herd books included the "Shorthorn Herd Book" published
by Coates in 1822. Other milestones in herd book development include:
•France: First cattle herd book in 1855
•Germany: First herd book in 1864
•Netherlands: First herd book in 1874
•Denmark: First herd book in 1881
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History
Modern Breeding Advances
After World War II, several animal breeding projects were initiated with substantial funding from the US
Department of Agriculture. These long-term investigations led to significant achievements across the dairy,
poultry, swine, sheep, and beef industries.
Livestock Breeding in Nepal
Livestock breeding efforts in Nepal officially began in 1952 (2008 BS) with the establishment of the
Livestock Improvement Section under the Department of Agriculture (DOA) in Singha Durbar. Key
milestones include:
•1850/51 AD: Import of cows from the UK by Prime Minister Jung Bahadur Rana.
•1952 (2008 BS): Establishment of the Livestock Improvement Section and grading up with exotic breeds.
•1953: Import of 20 Sindhi cows and 2 bulls from Pakistan.
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History
1957: American Heifer Project donated 8 Jersey and 8 Brown Swiss cows, along with 2 bulls of each breed.
1961 (2017/18 BS): Artificial insemination (AI) system began with fresh semen. The AI project was established
at Tripureswor.
1962: First AI service extended to farmers' herds, strengthening the crossbreeding program. Four breeds Jersey,
Brown Swiss, Ayrshire, and Holstein Friesian were used for cattle improvement programs.
1980/81 (2037/38 BS): Establishment of a Liquid Nitrogen Plant.
1985/86 (2041/42 BS): The Animal Breeding Division was shifted to Khumaltar, focusing on AI activities for
cattle and buffalo.
1988/89 (2046 BS): Formation of the Central Animal Breeding Division under NARSC and initiation of the AI
program, named Artificial Insemination Services under DLS.
1991/92 (2048/49 BS): Renamed as Animal Breeding and Artificial Insemination Program under the DOAD.
1995/96 (2052/53 BS): Returned to DLS with the name Animal Breeding and AI Section.
2001/02 (2058/59 BS): Relocated from Khumaltar to Pokhara.
2004/05 (2061/62 BS): Renamed as the National Livestock Breeding Center (NLBC).
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Indigenous Breeds and their economic values
➢Indigenous breeds refer to domesticated animal varieties that have evolved naturally within a
specific geographical region, adapting to local environmental conditions and cultural
practices.
➢These breeds are recognized for their unique characteristics, disease resistance, climatic
stress tolerance, and suitability for specific production purposes.
➢Economic Importance: Contribution to food security, local livelihoods, and genetic diversity
preservation.
➢Livestock Diversity in Nepal: Nepal is home to 25 locally adapted breeds spanning seven
livestock species, including cattle, buffaloes, sheep, goats, pigs, horses, and poultry.
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Economic and Cultural Significance
•Indigenous Breeds: Lulu, Achhami, Siri, Pahadi, Yak, Terai, Khaila
•Integraltomilkproductionandagriculturalwork.
•Serveasdraughtanimals,particularlyintheplainsandhillyregions.
•Widelyraisedbysmallholderfarmersfordairyfarmingandincome
generation.
Cattle:
•Crucial for mountain communities, providing milk, meat, and wool.
•Transportservicesaspackanimalsinremoteareas.
•Theysupportthesubsistenceeconomybyofferingessentialresourcesfor
food,clothing,andtransportationinhigh-altituderegions.
Yaks:
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Economic and Cultural Significance
•Indigenous breed: Terai, Khari, Chyangra, Sinhal. Economically significant due to
their adaptability, hardiness, and multifunctional uses. Thrive in diverse
environments, providing meat, milk, and fiber, serve as vital sources of nutrition and
income for rural households. Goat meat is in high demand locally and
internationally, while pashmina from Chyangra goats commands premium prices in
the textile industry. Their milk is used to produce various dairy products, supporting
food security and rural economies.
Goat:
•Indigenous breeds: Lampuchhre, Kage, Baruwal, and Bhyanglung. Economically
important for their adaptability, hardiness, and diverse uses. Provide meat, wool, and
milk, serving as vital sources of nutrition and income for rural communities, while
their wool supports the textile industry. Sheep meat is in high demand locally and
internationally, contributing to food security and economic growth. Conservation of
these breeds ensures genetic diversity, enhances rural livelihoods, and promotes
sustainable agriculture.
Sheep:
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Economic and Cultural Significance
•Indigenous breeds: Sakini, Ghanti Khuile, Dumse/Puwank Ulte. Crucial for their
adaptability, disease resistance, and productivity. Provide meat and eggs, supporting
rural livelihoods and enhancing food security. These breeds require minimal inputs
and thrive in local conditions, making them ideal for smallholder farmers. Their role
in traditional ceremonies and cultural practices adds to their economic and cultural
value. Conservation efforts ensure their sustainability and contribution to rural
development.
Poultry:
•Indigenous pig breeds in Nepal, such as Hurrah, Chwanche, and Bampudk.
Economically significant for their adaptability, efficient feed conversion, and high-
quality meat production. They thrive in diverse climates and require minimal
management, making them ideal for rural communities. These pigs provide essential
income and nutrition, enhancing livelihoods and food security. Additionally, they
hold cultural value in traditional practices, further contributing to their importance.
Conservation supports sustainable development and maintains genetic diversity.
Swine:
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Economic and Cultural Significance
•Indigenous breeds in Nepal: Gaddi, Lime, and Parkote.
•Highlyadaptabletodiverseclimates,thrivinginbothplainsandhillyregionswhile
offeringresiliencetodiseases.Theyproducehigh-qualitymilkforthedairyindustry
andprovidedraughtpowerforagriculturalwork.Theirmeatservesasanimportant
proteinsource,whiletheirconservationhelpspreservegeneticdiversity.These
buffaloessupportlocallivelihoodsbyofferingmultipleproductsandreducing
dependencyonexternalinputs.
Buffalo:
•Indigenous Jumli horses in Nepal hold economic importance as resilient, multi-
purpose animals. They serve as reliable transportation in mountainous terrain,
supporting tourism and trade. Additionally, they have cultural significance and are
used in festivals and ceremonies, contributing to local livelihoods and cultural
heritage preservation.
Horse:
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Animal genetic resources and Sustainable Development
➢Animal Genetic Resources (AnGR) refer to the genetic material of domesticated
animal species, which includes a variety of breeds, populations, and individuals that
possess unique genetic traits.
➢These resources are crucial for the development, improvement, and sustainability of
livestock systems worldwide.
➢AnGR encompass all species, breeds, and strains of animals that have economic,
scientific, or cultural value to agriculture.
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Importance of Animal Genetic Resources (AnGR)
Improvement of Livestock Breeds: AnGR facilitate the development of
new and improved breeds through crossbreeding with exotic species. This
allows for enhanced traits such as increased productivity, disease
resistance, adaptability to local climates, and resilience to environmental
stresses. High-yielding and adaptive breeds are crucial for improving
agricultural efficiency and meeting the growing demand for food products.
Production of High-Quality Products: Indigenous animal breeds provide
superior quality products like pashmina from Chyangra goats, which is
highly valued in the textile industry. Additionally, local breeds contribute to
the production of high-quality milk, meat, eggs, and fiber. These products
support local economies and enhance food security by providing vital
nutritional resources.
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Draft Power and Transportation: Indigenous breeds, such as
local cattle, provide critical draft power for plowing fields and
transporting goods, especially in regions where mechanized
equipment is not viable. Mules and local horses play an essential
role in transportation, particularly in high hills and mountainous
terrains, facilitating trade, tourism, and connectivity in remote
areas.
Socio-Cultural Importance: AnGR have significant socio-
cultural roles, particularly in rural communities. Indigenous
animals are used in festivals, ceremonies, and traditional practices,
helping preserve cultural heritage. These animals are often
intertwined with local customs, rituals, and lifestyles, contributing
to the social fabric of rural societies.
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Agricultural Input: Provide valuable farmyard manure (FYM), which is essential for
maintaining soil fertility in smallholder farming systems.
Disease and Parasite Resistance: Many indigenous animal breeds exhibit natural resistance to
local diseases and parasites, reducing the need for costly veterinary care.
Genetic Diversity and Biodiversity Conservation: AnGR are a key component of genetic
diversity, which is vital for maintaining the resilience of livestock populations to changing
environmental conditions, climate change, and emerging diseases.
Economic Contribution: The management and preservation of AnGR contribute to the national economy
by supporting rural livelihoods, increasing agricultural GDP (AGDP), and creating income opportunities
for farmers, breeders, and communities involved in the production and sale of purebred stocks. 25

Animal Genetic Resources and Its Significance
•Animal genetic resources (AnGR) refer to the genetic material found in
domesticated and wild animal species that contribute to agricultural production and
biodiversity.
•Genetic resources refer to the diversity of alleles and genetic traits present within a
population of living organisms.
•Genetic diversity is vital for the adaptability, resilience, and productivity of
livestock.
•It allows animals to adjust to changing environmental conditions, resist diseases,
and enhance productivity through genetic improvement programs.
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Sustainable Development
➢Sustainable development refers to meeting the needs of the present without
compromising the ability of future generations to meet their own needs.
➢This principle underpins efforts to ensure environmental conservation, economic
growth, and social equity for long-term global well-being.
Boby Basnet/Assistant Professor
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Role of Animal Genetic Resources (AnGR) in Sustainable
Development
Preserving Genetic Diversity: AnGR store unique traits
developed over centuries, like disease resistance and adaptability.
Diversity ensures livestock can handle environmental changes and
emerging diseases.
Adapting to Climate Change: Breeds with traits like heat
tolerance and drought resistance can survive in harsh climates.
Maintaining genetic diversity helps create resilient livestock
systems.
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Ensuring Food Security: Indigenous breeds provide milk, meat, eggs,
and income, especially for small farmers. They are vital for rural
nutrition and economic stability.
Supporting Livelihoods: Local breeds are a source of income and
resources for rural communities. They contribute significantly to
sustainable rural economies.
Preserving Culture and Traditions: Many indigenous breeds are tied to
traditional practices and cultural festivals (e.g., Yak blood-drinking
ceremonies). Protecting AnGR helps preserve cultural identity and heritage.
Driving Research and Innovation: Genetic diversity is crucial for breeding
better livestock with improved disease resistance and productivity.Research
supports developing sustainable livestock systems for future needs.
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Significance of AnGR for Future Challenges
Climate Change Adaptation
The ability to withstand heat
stress, drought, and fluctuating
resources is embedded in the
genetic traits of some local
breeds.
Thesetraitsmakesuchbreeds
invaluablefor livestock
productioninthefaceofglobal
climatechange.
Disease Resistance
Genetic diversity improves
resistance to diseases, reducing
reliance on chemical
interventions like antibiotics and
vaccines.
Thiscontributestosafer,
sustainablelivestocksystemsand
lowerproductioncosts.
Productivity Enhancement
Selective breeding programs can
use genetic traits from diverse
populations to improve
productivity in livestock without
compromising sustainability.
Geneticimprovementcanaddress
issueslikefeedefficiencyand
fertility,directlybenefiting
farmers.
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2. Rare breeds of different species of animal and
their characteristics; reasons for being
endangered and strategies for conservation.
Boby Basnet/Assistant Professor
Animal Science
Boby Basnet/Assistant Professor 31

Rare breeds of different species of animal and their
characteristics
➢Rare breeds are livestock, or poultry breeds that are uncommon or at risk of
extinction.
➢These breeds often hold unique genetic traits, historical significance, or cultural
importance.
➢To preserve their genetic diversity for future generations, conservation efforts are
undertaken.
➢Such efforts typically include breeding programs, educational initiatives, and policy
support to promote sustainable management and prevent the loss of rare breeds.
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Buffalo
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Characteristics Lime Parkote Gaddi
Distribution Low to mid hill and river basins of the
western region
Hilly areas, mostly in western
region
Far western mid to high hill
region
Body and ColorGray coat color, gray brown or
blackish skin color, black muzzle,
grayish, brownish or whitish eye brow,
grayish, brownish or whitish leg
markings, whitish chevron marks
around the neck and brisket.Whitish
or greyish markings are present on
their legs below the knees. Eyebrows
are white. Lime is the smallest one in
terms of body size and weight.
Black in colour, occasionally
brown and light brown in colour.
May or may not have leg
markings. Black muzzle.
Long face and flat head.
Parkote have medium sized body
with longer body length.
Black in colour with white round
patches on the forehead.
Occasionally, in brown and light
brown colour. Long face and flat
head.
Gaddi re compact and massive
with angular body shape and
sloped hip position.
Horns Relatively small, sickle-shaped, and
curved toward the neck.
Sword shaped directed towards
the back of the body.
Horns are long half curved.
Temperament Semi-wild Semi-wild Docile and well-tractable
Weight 300-350 kg 300-400 kg 300-400 kg
Milk yield
(l/day)
2-3 l/day 2-4 l/day 3-4 l/day
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Cattle
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Characters Lulu Acchami Khaila
DistributionDolpa, Manang, Mustang Achham, Bajhang, Bajura and
Doti.
Far western mid to high hill region
Body/Color Humpless, black, brown, grey and
white that is black, brown, grey,
white, spotted black and white.
hair is found to be long, ruffled,
densey, and dull.
Humped, Smallest breed of
cattle. Coat color is black
brown, grey, white, spotted
black and white. Ear is medium
sized and straight. Color of
muzzle and hoof is black.
Humped. Small to medium-sized head.
Shoulders are broad and strong to
support pulling plows and carrying loads.
Muzzle is generally black or dark-
colored
Horns Medium to small sized horns,
curve slightly forward
Sword shaped directed towards
the back of the body.
Short, upward-pointing horns with a
slightly curved shape.
TemperamentSemi-wild Docile to Semi-wild Docile and well-tractable
Weight (kg)120-160 120-150 150-180
Milk yield 1.6l/day 2-4l/day 2.5l/day
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Characteristics Siri Terai Hill
Distribution Ilam Tropical plains of Terai regionHlls and mountain of Nepal.
Body and ColorHumped type cattle. Medium body
sized cattle breed. White and black
patches on their bodies and some are
reddish color. Siri cattle are the highest
milk yielders among the indigenous
cattle, well-developed udder, good
milking ability. Wide flat forehead and
a thuft of hair (Furka) in the middle of
forehead. Small and straight ears.
Humped, light colored animals,
mostly white-coated with black
skin and occasionally in black
and other mixed color. Straight
ear.
Humped, Black in color
occasionally in blackish brown
and mixed color. Male are good
drought animals and capability to
ploughing on narrow, sloppy,
undulating terrain land. Pahadi
cattle are small to medium sized.
Compact cylindrical body, short
legs, medium hump, horizontally
placed ears and comparatively
longer tail than other indigenous
cattle
Horns Sharp horns projecting forward and
slightly upward.
Sharp and Projecting upwards Medium sized curved in lateral
and upward direction.
Temperament Docile to semi wild Docile to Semi-wild Moderately wild
Weight 200-300 210 200-250
Milk yield 4.5l/day 2.1/day 1.1l/day
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Yak/Nak
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Yak
1.Habitat: Raised in the trans-Himalayan region, typically at altitudes above 3000 meters above sea
level.
2.Physical Appearance
a.Color: Predominantly black, but other colors such as white, fawn, brown, grey, and spotted black-
and-white are also common.
b.Ears: Straight with a swampy switch tail.
3. Temperament: Wild temperament.
4. Production: Produce an average of 0.8 kg of milk over a lactation period of 5 months (160 days).
5. Body Weight: Yak: 355 kg and Nak: 325 kg
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Sheep
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IndicatorsKage Baruwal Bhyanlung Lampuchhre
Geography300-1500 masl 1500-2500 masl 2500-4000 masl Terai Region
CharactersShort-tailed. Smallest
indigenous sheep breeds
with better prolificacy
(18%twinning). Males had
sickle shaped horns while
females are mostly polled.
Coat colour is white in the
body except on head
region. Head is mostly
brown. Birth 3 kids in 2
years.
Smallest ear among the
Nepalese breeds. It has
ears of 7cm length.
Body colour is mostly
white with variation in
head colour from white
or black. Fleece colour
of Baruwal sheep were
mostly white (82%)
followed by brown
(10%), black and white
(5%) and pure black
(3%). Ewes are mostly
polled but rams have
51 cm curved horns.
Both sexes carry wide-
spreading spiral horns
and some males have
multiple horns (Wilson,
1997). horn length
depending on the
location ranging from
19 cm in Solukhumbu
to 35 cm in Mustang
district. Body colour is
mostly white with
variable head colour
from white, brown and
black.
Ewes are polled while
the ram possesses
curved horn of 31 cm.
Breed has 12 cm short
ear. Lampuchhre is a
hardy long-tailed
breed. Tail length is 34
cm.
Weight 20-25 kg 30-40 kg 60-90 kg 30-40 kg
Wool/year500 gm 750 gm 1000gm 500-1000 gm
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Goat
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Indicators Terai Khari Singhal Chyangra
Geography60-300 300-1500 1500-2500 Above 2500
CharactersTerai goat is a medium
sized animal .Popular
for meat production
and taste. Hardy and
suitable for hot climate
Khari goats are the
principal goat breed in
the country. Quite
prolific breed having
twinning commonly.
Good breed for high hills
and are suitable for pack
animals. Largest goat
breed in the country used
for meat and draught
purpose. Not prolific
breed with single
progeny at a time. Very
hardy and suitable for
adverse climate.
Chyangra goats are good
breed for high hills and
mountains and are
suitable for meat and pack
animals. Not prolific breed
(single kid) . Very hardy
and suitable for adverse
climate.
Sexual
Maturity
11 months 10 months 12 months 13 months
Kids at birth1.4 1.6 1.1 1
Weight (kg)18-35 15-25 30-35 25-30
ConditionDifficult to find pure
breed
Normal to find pure breedDecreasing Decreasing
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Swine
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Chawanche Hurrah Bampudke
➢They located in low to mid hills and are
good scavenger animals.
➢They are black in color.
➢Long and straight snout .
➢Small erect ears .
➢Its barrel is dropping type .
➢Female has 8 to 12 teats .
➢Average adult weight is 35 kg ranging
from 25 to 40 kg .
➢Long and straight tail .
➢Small body size and short height.
➢The top length (from head point to the
base of tail) is 76 cm and heart girth is
86 cm.
➢They are semi-wild in nature
➢They located in terai region
(tropical and subtropical) and are
mainly used for meat.
➢Its body color is completely
grayish black or rust brown with
rough skin.
➢Small and erect ears.
➢Straight snout.
➢Hair is straight.
➢Long and strong legs.
➢Straight and long tail.
➢Female has 8 to 12 teats .
➢The average adult weight is 45 kg
ranging from 40 to 55 kg.
➢The top length (from head point
to the base of tail) is 79 cm and
heart girth is 88 cm.
➢They are semi-wild and are active
in nature

➢Found in Humla, Bajura
(Boarder to Tibet).
➢They are normally red and
brown color and sometime
found in black color .
➢Top length (from head point to
the base of tail) is 45 cm .
➢Heart girth is 52 cm.
➢Female has 8 to 12 teats .
➢Their average adult body
weight is 20 kg (ranges from 18
to 25 kg).
➢The indigenous pig breeds are
high fertility and have good
reproductive characters such
as litter size and farrowing
intervals.
➢Bampudke pigs are found in
both domestic and wild form.
45

Poultry
Boby Basnet/Assistant Professor 46

Sakini Ghanti Khuile Pwankh ulte
➢Sakini is an attractive breed among
three indigenous breeds of chicken in
Nepal.
➢The feather color varies from black to
red, spotted black and white, red and
white, red and black.
➢Skin color varies from white to yellow.
➢Earlobe color of sakini chicken varies
from pink to red.
➢Shank is yellow to brown in color.
➢This breed has single or rose type
comb of red color.
➢They have brown to black legs.
➢The egg production capacity is 70 to
80 /year. The average adult body
weight is 1.5 to 2.0 kg.
➢They have featherless neck i.e.
naked neck.
➢Black to red or some times red
and black feather color.
➢They have white to yellow skin
color.
➢They are characterized by pink to
red ear lobe color.
➢Shank is yellow to brown in
color.
➢Ghanti khuile chicken have red
colored single or rose type comb.
➢They are also characterized by
brown to black legs.
➢The egg production capacity is
60 to 80 /year. The average adult
body weight of male is 1.6 and
female is 1.30 kg.
➢They have ruffled feathers
(curved outwards) all over the
body.
➢They comprise with Sakini breed
in their feather color.
➢Skin color of Pwankh ulte
chicken is white to yellow.
➢Have pink to red earlobe color.
➢Shank is yellow to brown in
color.
➢Pwankh ulte chicken have single
or rose type comb of red color.
➢They have brown to black legs as
other indigenous breeds of
chicken.
➢The average adult body weight
of male is 1.0 and female is 0.9
kg.
➢The egg production capacity is
70 to 85 /year. 47

Jumli horse
➢Found in Dang, Dolpa, Kailai, Jumla,
Kanchanpur.
➢Medium sized with strong muscular body
structure.
➢Mainly on white, red and grey color. Generally,
Jumli horses have the solid color but some have
combination of two or more colors.
➢Under the feet and tail are normally grey in
colour.
➢Grey colored horses are changed into white
colour after some time with the increase in their
age. Some Jumli horses are also found black in
color and some are mixed white.
➢The average adult body weight is 196 kg.
➢The healthy and adult can carry up to 80-100 kg.
➢Female are ready for breeding in 3 years but male
became mature within 2.5 to 3 years
➢The Gestation period is one year (365 days).
Boby Basnet/Assistant Professor 48

Reasons for the Endangerment of Indigenous Breeds
Limited
Institutional
Support
Inadequate funding, research, and extension services for conservation.
Lack of policies and awareness for the protection of indigenous breeds.
Habitat Loss and
Fragmentation
Deforestation, urbanization, and agricultural expansion lead to reduced
grazing areas.
Habitat degradation threatens survival.
Genetic Dilution
through
Crossbreeding
Introduction of exotic breeds for higher productivity dilutes the genetic
purity of indigenous breeds.
Unique traits and adaptability are lost in crossbred populations.
Boby Basnet/Assistant Professor 49

•Extreme weather events and climate variability disrupt native breed adaptation.
•Changesintemperatureandforageavailabilityaffectsurvivalandreproduction.
Climate Change and Environmental Stressors
•Small populations and limited breeding programs cause genetic erosion.
•Reducedgeneticdiversityincreasessusceptibilitytodiseasesandstress.
Genetic Erosion and Inbreeding
•Epidemic outbreaks (e.g., bird flu in poultry) threaten large populations in a short time.
Diseases
•Mechanization and modernization favor exotic breeds over indigenous ones.
•Traditionallivestockhusbandrymethodsarebeingreplacedbyintensivesystems.
Changing Agricultural Practices
•High-yielding exotic breeds are preferred for meat, milk, and growth rates.
•Reducedeconomicincentivesforfarmerstomaintainindigenousbreeds.
Market Demand and Commercialization
50

Conservation of Animal Genetic Resources (AnGR)
•Conservation of AnGR refers to all human activities, strategies, plans,
policies, and actions undertaken to ensure the diversity of AnGR is
maintained, contributing to food security, agriculture, and productivity
Boby Basnet/Assistant Professor
51

Methods of Conservation
1. In-Situ Conservation
•In-situ conservation involves conserving animals in their natural environment where they have evolved.
•Farmers work together to conserve breeds like Nepal’s Chyangra goat and Yak in the Himalayan region.
•Conservation of breeds like Khaila cattle in Nepalese hill regions through traditional farming practices.
Advantages
•Animals are conserved in a stress-free, natural environment.
•Biodiversity is protected broadly and permanently.
•Disadvantages
•Animals are at risk from diseases, parasites, predators, and other natural threats.
•Higher chances of inbreeding.
•Vulnerability to natural disasters.
Boby Basnet/Assistant Professor 52

2. Ex-situ conservation
It involves preserving genetic material (e.g., semen, embryos, DNA) or live animals outside
their natural habitat.
Methods:
Cryopreservation: Freezing semen, embryos, or DNA in liquid nitrogen for long-term
storage. Example: Semen banks for breeds like Jersey crossbreeds in Nepal.
Conservation Farms: Establishing farms or zoos to maintain live populations of rare breeds.
Advantages:
➢Provides a backup in case a breed becomes extinct in situ.
➢Allows for controlled reproduction and breeding.
Challenges:
➢High cost of facilities and maintenance.
➢Loss of natural adaptability when animals are bred outside their environment.
Boby Basnet/Assistant Professor 53

Strategies for Conservation of AnGR
1.Development of conservation policies and frameworks.
2.Identification, classification, and documentation of indigenous breeds.
3.Promotion of in-situ conservation through community participation.
4.Strengthening ex-situ conservation with gene banks and cryopreservation.
5.Research and development on genetic traits and breeding programs.
6.Providing financial support, subsidies, and livestock insurance.
7.Promoting utilization and value addition for indigenous breed products.
8.Regular monitoring, evaluation, and establishment of early warning systems.
Boby Basnet/Assistant Professor
54

3. Genetic principles of animal breeding
Boby Basnet/Assistant Professor
Animal Science
Boby Basnet/Assistant Professor 55

Assignment Topic
1.The principle of segregation (1-17)
2.The principle of dominance (18-34)
3.The principle of independent assortment (35-51)
Boby Basnet/Assistant Professor 56

➢Genetics is the science of heredity and variation.
➢It is the scientific discipline that deals with the differences and similarities among related
individuals.
➢For many years, managers of agricultural systems have manipulated the genetic makeup
of animals to:
a.Improve productivity
b.Increase efficiency
c.Adaptability
➢Successful manipulation of the genetic composition of animals requires a depth
understanding of fundamental principles of genetics.
Boby Basnet/Assistant Professor 57

Mendelian genetics
•Mendel proposed three principles to describe the transfer of genetic
materials from one generation to the next.
a.The principle of dominance
b.The principle of segregation
c.The principle of independent assortment.
Boby Basnet/Assistant Professor 58

Law of Dominance
•When two homozygous individuals
with one or more sets of contrasting
characters are crossed the alleles
(characters) that appear in F1 are
dominant and those which do not
appear in F1 are recessive.
•Phenotypic Ratio: 3:1
•Genotypic Ratio: 1:2:1
Boby Basnet/Assistant Professor 59

•In animals, chromosomes are paired and therefore genes are paired.
•These paired genes code for the same trait, but they are not identical.
•They can have different forms, known as alleles.
•For example, sheep and cattle can be polled or horned.
•One gene codes for this trait and the two possible forms (alleles) of gene are polled
or horned.
Boby Basnet/Assistant Professor 60

Morgan experiment on Drosophila
In 1910, Thomas Hunt Morgan conducted an experiment with fruit flies (Drosophila) that led
to the discovery of sex-linked inheritance and the first localization of a gene to a
chromosome.
Experiment: Morgan bred thousands of fruit flies and observed that all of the offspring had
red eyes. He found one white-eyed male. He bred the white-eyed male with a red-eyed
female.He observed that some of the first generation offspring had white eyes, but more of
the second generation did.He observed that all of the white-eyed flies in the second
generation were male.
Results: Morgan concluded that the gene controlling eye color was on the same chromosome
that determined sex.He concluded that chromosomes carry the genes that allow offspring to
inherit traits from their parents.He confirmed that the Mendelian theory of inheritance was
accurate. Genotypic ratio: 1:2:1 and Phenotypic ratio: 3:1.
Boby Basnet/Assistant Professor 61

Boby Basnet/Assistant Professor 62

Chromosomal Theory of Inheritance
•The Chromosomal Theory of inheritance, proposed by Sutton and Boveri, states
that chromosomes are the vehicles of genetic heredity. Neither Mendelian genetics
nor gene linkage is perfectly accurate; instead, chromosome behavior involves
segregation, independent assortment, and occasionally, linkage.
•Morgan assumed eye colour genes that passed down generation are sex-linked.
•Autosomes (Not sex chromosomes): 22 pairs
•Sex-Chromosomes: 1 Pair
•XX= female, XY= Male
•Sex linked defined as characters traits with sex chromosomes
•The characters which usually passed down to the generation with particular to the
sex will be sex linked.
Boby Basnet/Assistant Professor 63

Genetic Linkage
•Genetic linkage is the tendency of genes that are close together on a
chromosome to be inherited together.
•This happens during meiosis, the phase of sexual reproduction when
homologous chromosomes pair up and exchange segments.
64

Law of segregation (Law of purity of gametes)
•On crossing a pair of contrasting characters alleles come
together without mixing and separates out during gametes
formation.
65

•In case of animals, when crossing homozygous dominant parents
(PP×PP), all offspring will be homozygous dominant polled individuals.
•When crossing homozygous recessive parents (pp × pp) all the offspring
will be horned (homozygous recessive) individuals.
•When crossing a heterozygote parent with a homozygous dominant parent
(Pp × Pp), the expected offspring would occur in a 1:1 ratio of
homozygous dominant to heterozygous individual.
•Phenotypically, all offspring would be polled, when crossing a
homozygous dominant parent with a homozygous recessive parent (PP ×
pp), all offspring would be heterozygous and polled.
•If two heterozygous parents are crossed (Pp × Pp) one can expect a
genetic ratio 1:2:1 with one homozygous dominant polled, two
heterozygous polled, and one homozygous recessive horned individuals
Boby Basnet/Assistant Professor 66

Law of Independent Assortment
•This law is based on dihybrid cross.
•It describes how different genes or alleles present on separate chromosomes
independently separate from each other during formation of gametes. These alleles
are then randomly united in fertilization.
•In dihybrid cross F2 Phenotypic ratio (9:3:3:1) indicates that the two pairs of
characters behave independent of each other.
•It can be concluded that the two characters under consideration are assorted
independently giving rise to different combinations.
•The alleles of different genes assort or segregate independently each other,
PpBb×PpBb gives 9:3:3:1.
Boby Basnet/Assistant Professor 67

•In case of animal there are multiple traits that need to be consider
when mating animals.
•For example, consider that cattle can be horned or polled and white-
faced or red faced.
•The horns and red-faced coloring are recessive traits.
•If two individual with two pairs of heterozygous genes (each affecting
a different trait) are mated, the expected genotypic and phenotypic
ratios would be: 1:2:1:2:4:2:1:2:1 and 9:3:3:1 respectively.
Boby Basnet/Assistant Professor 68

69

Boby Basnet/Assistant Professor 70

GENE ACTION
Boby Basnet/Assistant Professor
Animal Science
Boby Basnet/Assistant Professor 71

Gene Action
Gene action can be categorized into two main types namely,
Additive Gene Action Non-Additive gene action.
Knowledge of gene action helps in the selection of parents for use in the hybridization
programs and also in the choice of appropriate breeding procedure for the genetic
improvement of various quantitative characters.
Gene action refers to the behavior or mode of expression of genes in a genetic
population.
Boby Basnet/Assistant Professor 72

Gene Action
Additive gene action Non- additive gene action
Epistasis
1)Dominant
2)Recessive
3)Duplicate Dominant
4)Duplicate Recessive
5)Dominant Recessive
Interaction
6)Duplication genes
with cumulative effect
1)Complete Dominance
2)Incomplete Dominance
3)Co-Dominance
4)Over Dominance
5)No Dominance
Dominance

Additive Gene/ Non- additive Gene
Additive Gene Action is referred to as
the phenomenon in which the two
alleles of the gene contribute equally to
the production of the phenotype.
Non additive or dominance gene action
refers to the phenomenon in which one
allele is expressed stronger than the
other allele.
Dominance
Does not show any dominance, both
alleles are expressed equally in additive
gene action.
May show complete dominance or
incomplete dominance in non-additive
gene action.

(Complete) Dominance
❑Example- Polled/ horned condition in cattle
X
Polled Angus cow
PP
Horned Hereford bull
pp
PP Pp
Pp pp
P p
P
p
X
❑P allele for polled is completely dominant
over p allele for horned
❑Definition
Form of dominance in which the expression
of heterozygote is identical to the expression
of homozygous dominant genotype
F
1
F
2
Pp

Incomplete (Partial) Dominance
❑Example- Feather colour in Andalusian chicken
Definition
➢One allele is partially dominant to other→ blending of phenotype (dominant allele is not fully
expressed).
➢Expression of heterozygote is intermediate to the expression of homozygous genotypes and more
closely resembles the expression of homozygous dominant genotype.
➢Incomplete dominance is an exception toMendel's law of dominance.

Incomplete Dominance: Flower colour in Snapdragon

Co-Dominance
RR WW
WR
X
Red Shorthorn bull White Shorthorn cow
Roan coat colour
❑Example: Roan coat colour in Shorthorn cattle
❑Both alleles of a gene are dominant and expressed in
heterozygote.
❑Expressed phenotype is the combination
of phenotypes of both alleles.
RR
WWRW
RW
R
R
W
W

Over-dominance
➢Expression of heterozygote is more extreme than
both of homozygotes.
➢Heterozygote expresses the phenotype outside of
range of homozygote phenotypes.
➢BUT most closely resembles the expression of
homozygous dominant phenotype.
➢Often called “Superior heterozygote” but “Extreme”
might be more correct.
➢ Example- survivability in wild rats.

Vit K
RR rr
Susceptible to warfarin
poisoning
Resistance to warfarin poisoning
But needs higher Vit K
Rr
Resistance to warfarin
Can survive Vit K deficiency
Wanna try cakes
not Vit K
❑With respect to survivability,
warfarin locus displays
over dominance

Epistasis
➢Derived from ancient Greek work for “stoppage.
➢It is phenomenon in which effect of one gene or gene pair
(epistatic) at one locus masks or modifies the effect of another
gene or gene pair (hypostatic) at another locus.
➢Epistasis is essentially "against" the idea ofindependent gene effects.
➢Epistasis alters the Mendel’s dihybrid phenotypic ratio of 9:3:3:1.
Types
1) Dominant Epistasis/Masking Gene action (12:3:1)
2) Recessive Epistasis/Supplementary Interaction (9:3:4)
3) Duplicate Dominant (15:1)
4) Duplicate Recessive (9:7)
5) Dominant Recessive Interaction (13:3)
6) Duplicate Genes with Cumulative Effect (9:6:1)

Boby Basnet/Assistant Professor 83

4. Variation, Causes of variation and
Importance of variance
Boby Basnet/Assistant Professor
Animal Science
Boby Basnet/Assistant Professor 84

Variation
•Heritable difference among individual due to difference in the information passed
from parents to offspring.
•Genetic variation is transmitted to future generation but due to environmental
difference is not transmitted.
•Environmental variation is often large and many of the environmental influences
which causes variation are not well defined.
•Variation: size, rate of growth, efficiency of feed utilization, carcass, characteristics,
disease resistance, milk production, color, wool quality.
Boby Basnet/Assistant Professor 85

Types of Variation
1. Genetic Variation
Differences in the genetic material (DNA) among individuals.
Sources:
•Mutation: Changes in the DNA sequence.
•Recombination: Mixing of parental genes during reproduction.
•Gene flow: Movement of genes between populations.
Examples:
•Coat color variations in goat.
•Horn size differences in cattle.
Boby Basnet/Assistant Professor 86

2. Environmental Variation
Differences caused by environmental factors rather than genetics.
Examples:
•Size differences due to nutrition.
•Changes in fur thickness due to climate.
3. Phenotypic Variation
•Observable differences in traits, resulting from both genetic and environmental influences.
Examples:
•Height differences in horses due to both breed and feeding.
•Milk production differences in dairy cows.
Boby Basnet/Assistant Professor 87

Causes of variation
•Variation in animals refers to the differences
observed among individuals within a species or
between different species.
•Variation in animals arises from differences in
their genes and their environment.
•The main causes are:
a.Genetic cause
b.Phenotypic cause
Boby Basnet/Assistant Professor 88

Genetic Causes
1.Recombination:
➢Primary source of genetic variation.
➢New combination of existing genes through gamete formation
➢ Mixing of genes during reproduction that produces unique offspring.
Boby Basnet/Assistant Professor 89

2. Mutations:
➢A change in gene (structure of coding) that may result in a change in phenotype of an
individual, or change in code sent by gene to rhizome to assemble a certain proteion
➢Changes in the DNA that can create new traits (e.g., new fur color).
•Gene Flow: Movement of genes between populations through migration.
•Sexual Reproduction: Combines genes from two parents, creating diversity.
Boby Basnet/Assistant Professor 90

3. Chromosomal behavior
•Change in the normal arrangement of chromosomes
•Deletion, Duplication, Inversion, Translocation
Boby Basnet/Assistant Professor 91

Phenotypic Cause
i. Variation due to heredity
•Heredity refers to the genetic make up of an individual that is fixed at
the time of fertilization and remains same for the remainder life of an
individual
•Genetic make up of an individual is determined by genes that are
received from parents
•Inbred line are nearly identical to each other.
Boby Basnet/Assistant Professor 92

ii. Variation due to environment
•No twins individual even of same sex are exactly alike because the
environment is never same in different places at different time.
•The environment does not directly change the genetic makeup but
determine the degree of expression.
•The environmental factors are not transmitted from parents and
offspring.
Boby Basnet/Assistant Professor 93

iii. Variation due to H×E interaction
❑It means that animal of a certain genotype may perform better in one
environment than in other i.e. one environment permits the expression
of genetic character in a breed or strain which other does not.
Boby Basnet/Assistant Professor 94

Importance of Variation in Animal Breeding
1. Genetic Improvement
•Enables selection of desirable traits (e.g., higher yield, disease resistance).
•Promotes hybrid vigor (heterosis).
2. Adaptability
•Helps animals adapt to environmental changes.
•Improves stress tolerance.
3. Disease Resistance
•Reduces risks of inbreeding and associated disorders.
•Enhances immunity and resistance to diseases.
Boby Basnet/Assistant Professor 95

4. Economic Benefits
➢Optimizes production efficiency (e.g., feed conversion).
➢Meets specific market demands.
5. Conservation of Genetic Resources
➢Preserves rare breeds and biodiversity.
➢Ensures sustainability for future breeding.
6. Scientific Advancements
➢Facilitates research in genetics and biotechnology.
7. Ethical and Social Implications
➢Supports animal welfare by avoiding harmful traits.
➢Preserves traditional and culturally significant breeds.
Boby Basnet/Assistant Professor 96

5. Heredity: meaning and importance of
heredity; heredity and environment;
heritability, repeatability and their
estimates.
Boby Basnet/Assistant Professor
Animal Science
Boby Basnet/Assistant Professor 97

Heredity
•Heredity refers to the process by which traits, characteristics, or genetic
information are passed from parents to their offspring through genes.
•Heredity is fundamental to the genetic inheritance of various traits, including
physical characteristics (such as coat color, body size, and conformation),
production traits (such as milk yield, egg production, and growth rate), and
behavioral traits (such as temperament and social behavior).
•Heredity occurs via the genetic material (DNA) present in chromosomes, which
carry specific instructions for development, growth, and functioning.
Boby Basnet/Assistant Professor 98

Importance of Heredity
1. Improvement of Productivity: Heredity influences traits like growth rate, milk
production, egg-laying capacity, meat quality, and wool production. Through selective
breeding, these traits can be enhanced, increasing productivity over generations.
2. Trait Inheritance: Genetic traits such as disease resistance, body size, and production
efficiency are passed down through heredity. Breeders can select animals with desirable traits
to improve the genetic potential of future generations.
3. Genetic Variation: Heredity introduces genetic variation, essential for successful breeding
programs. Variation provides the foundation for selecting animals with favorable traits,
enhancing the overall genetic merit of a population.
Boby Basnet/Assistant Professor 99

Selection Response: By selecting animals with superior genetic traits as parents, the
likelihood of transmitting these traits increases. Over generations, this leads to
genetic improvement within the population.
Genetic Diversity: Maintaining genetic diversity is vital for long-term sustainability,
resilience against diseases, and adaptation to environmental changes. Effective
breeding balances selection with preserving diversity.
Breeding Value Estimation: Heredity aids in estimating breeding values
quantitative measures of an animal’s genetic merit. These values guide breeders in
making informed selection decisions.
Disease Resistance: Selective breeding can enhance disease-resistant traits, reducing
the risk of illness, lowering veterinary costs, and improving overall herd health.
Boby Basnet/Assistant Professor 100

Adaptation to Environment: Heredity allows animals to adapt to specific environments, such as
heat-tolerant cattle or drought-resistant goats, improving their survival and efficiency.
Conservation of Desired Traits: Controlled breeding preserves desired traits like fertility,
temperament, and feed efficiency, ensuring animals meet specific production goals.
Hybrid Vigor (Heterosis): Crossbreeding utilizes heredity to create hybrid vigor, resulting in
healthier and more productive offspring with enhanced performance.
Economic Benefits: Genetic improvements directly impact profitability by increasing production,
reducing costs, and enhancing the market value of animals.
Conservation of Endangered Breeds: Heredity is crucial for conserving endangered breeds and
propagating indigenous species, safeguarding valuable genetic traits.
Boby Basnet/Assistant Professor 101

Heredity and Environment
•Heredity and environment are two fundamental factors that influence the
traits and performance of animals.
•Heredity refers to the genetic blueprint passed from parents to offspring
through DNA, determining an animal's potential for traits such as growth,
reproduction, milk production, and disease resistance.
•On the other hand, the environment includes external factors like nutrition,
climate, housing, disease exposure, and management practices, which
significantly affect the expression of these genetic traits.
Boby Basnet/Assistant Professor 102

Interaction of Heredity and Environment
•The interaction between heredity and environment plays a vital role in determining the
traits and performance of animals.
•For example, a high-yielding dairy cow may not achieve its genetic potential for milk
production if subjected to poor feeding or suboptimal care, while even average-yielding
animals may perform exceptionally well under superior management.
•Similarly, traits like disease resistance and fertility, which are moderately heritable, depend
significantly on environmental factors such as hygiene, vaccination, and stress levels.
•Some traits, like coat color, are largely determined by heredity, while others, such as
productivity and reproduction, are more sensitive to environmental influences.
•Balancing heredity and environment is essential for achieving sustainable and productive
livestock systems.
Boby Basnet/Assistant Professor 103

Heritability
•Heritability refers to the degree to which a trait or characteristic can be passed from
one generation to the next.
•Heritability refers to the proportion of the total phenotypic variation controlled by
genetic rather than environmental factor.
•Heredity is the process of passing trait.
•Heritability quantifies how much of a trait is due to genetics.
•Heritability is always positive ranging from 0 to 1.
Boby Basnet/Assistant Professor 104

Types of heritability
A. Heritability in the broad sense (H²): It is the proportion of the phenotypic variation that is due to
genetic effects including additive, dominance and epistasis. It measure the strength of relationship
between the phenotypic values for a trait and genotypic value.
H²= Vg/Vp
H²= (Va+Vd+Vi)/Vg+Ve
Vg= genetic variation
Va= additive genetic variation
Vd= dominance genetic variation
Vi= epistatic genetic variation
Vp= phenotypic variation
B. Heritability in the narrow sense (h²): It is the proportion of the phenotypic variation that is due to
genetic effects including additive, dominance and epistasis.
h²= Va/Vp
Boby Basnet/Assistant Professor 105

Categories of heritability
1. Low heritability traits (h2<0.3): Production Trait
✓Reproductive traits (conception rate, traits related to fertility, little size etc).
✓ Longevity or productive life.
2. Moderate/medium heritable traits (h2 =0.3-0.5): Reproduction Trait
✓Milk yield, fat yield and protein yield.
✓Birth weight in sheep.
3. Highly heritable traits (h2>0.5): Qualitative Trait
✓Most of the qualitative traits (coat, color) shows high heritability.
✓The values of heritability ranges from 0.5-1 and no any traits are 100% heritable because
there is always the effect of environment either in trace amount or in large amount.
Boby Basnet/Assistant Professor 106

Importance of heritability
1.It helps in predicting the amount of progress or genetic gain that might be made in selection for a particular
trait.
2.With the knowledge of heritability estimates, it helps in choosing effective breeding plan. If the trait is
highly heritable; it indicates that additive gene action is important for that trait and the mating of best to
best should produce more desirable offspring.
3.If the heritability of the trait is high, the correlation between the phenotype and the genotype of an
individual, on an average should also be high and the selection on the basis of individual’s own
performance should be effective.
4.Low heritability estimates indicate that the correlation between genotype and phenotype is low. In this case,
while selecting animals much more attention must be paid to the performance of the collateral relatives and
the progeny.
5.Low heritability is also an indication of low additive gene action i.e. non-additive gene action such as
dominance, over-dominance and epistasis may be important. This makes it necessary to use special method
of selection and mating for greater improvement in the population.
Boby Basnet/Assistant Professor 107

Methods of Heritability Estimation
•Comparing the similarity between identical twins to the similarity
between dizygotic twins. Heritability= difference of identical twins/
difference of non-identical twins.
By comparing twin data
•Here, the performance of progeny and a group of selected individual is
compared to be the performance of their parents.
•Heritability= genetic progress/ selection differential.
Apparent heritability
•Regression analysis
•Theregressioncoefficientisameasureofhowmuchonevariableis
expectedtochangewitheachunitofchangeinanothervariableonthe
average.
Using co-relation:
•Because the members of the same family are genetically more alike than
individual from different families, an analysis of variance can be used to
compare variation within families to the variation among families.
Analysis of variance
(ANOVA)
Boby Basnet/Assistant Professor 108

Repeated Traits
•Repeated Traits are the traits for which individuals’ community have more
than one performance.
•For instance, of service conception, egg weight in poultry and staple length
in sheep, milk production in successive lactation.
•Repeated records are basically repeated phenotypic values for the trait.
Boby Basnet/Assistant Professor 109

Repeatability
It is a measure of strength of relationship between repeated records
for a trait in a population. Its value ranges from 0 to 1.
Repeatability estimate the expression of the same trait at different
times in the life of same individual.
Repeatability (r): It is the proportion of phenotypic variation that is due
to the genetic effects and permanent environmental effects.
r = (Vg + Vep)/Vp
Boby Basnet/Assistant Professor 110

•The genotype of an animal remains same
through its lifetime.
•The genotype is responsible for
expression of a trait.
•We observe variation in expression of
repeated traits.
•Since genotype is same the variation is
said to be affected by environmental
condition.
Cow A
Lactation No. Milk Production (liters)
1 1450
2 1530
3 1600
Boby Basnet/Assistant Professor 111

Repeatability Estimate
➢Repeatability Estimate is the expression of the
same trait at different time in the life of the same
individual.
➢Repeatability estimates are numerical values that
quantify the repeatability of specific traits in
animal breeding.
➢It can be estimated by interclass correlation
method.
Categories of repeatability
<0.2 Low repeatableFertility, litter
size
0.2-0.4 Moderately
repeatable
Growth traits,
milk yield
>0.4 Highly repeatableEgg weight, milk
composition
traits.
Boby Basnet/Assistant Professor 112

General Repeatability Estimates for Common Traits
Milk yield: 0.4-0.6
Milkfatpercentage:0.5-0.6
Dairy Cattle:
Growth rate: 0.3-0.4
Reproductivetraits(e.g.,calvinginterval):0.1-0.2
Beef Cattle:
Wool production: 0.4-0.6
Littersize:0.1-0.2
Sheep:
Egg production: 0.5-0.7
Eggweight:0.6-0.8
Poultry:
Growth rate: 0.3-0.5
Feedconversionefficiency:0.4-0.6
Swine:
Boby Basnet/Assistant Professor 113

Importance of repeatability
Prediction of production ability and animal’s next record.
If r is high: predict animal’s next record more accurately.
If r is low: predict animal’s next record low accuracy.
Repeatability is useful in estimating most probable producing ability
(MPPA) of the individuals in a herd and would make it possible to compare
and cull them more accurately on a standard basis.
For example: r high: cull poor performance animal.
R low: wait for more records to cull an animal.
Boby Basnet/Assistant Professor 114

Heritability Vs Repeatability
Aspect Heritability Repeatability
Definition
The proportion of total
phenotypic variance attributed to
genetic variance.
The proportion of total
phenotypic variance attributed to
genetic and permanent
environmental effects.
Symbol h² r
Factors Included
Only genetic variance (additive,
dominance, and epistasis).
Genetic variance + permanent
environmental variance.
Focus
Measures the genetic contribution
to a trait.
Measures the consistency or
repeatability of a trait over time.
Application
Used for predicting response to
selection in breeding.
Used to assess the reliability of
repeated measurements.
Importance in Breeding
Determines the potential for
genetic improvement.
Determines the reliability of
selecting individuals based on
repeated performance.
Boby Basnet/Assistant Professor 115

4. Breeding system and selection: principles,
basis, method and selection parameters;
important economic traits of livestock and
poultry; breeding plan.
Boby Basnet/Assistant Professor
Animal Science
Boby Basnet/Assistant Professor 116

Breeding System
➢Breeding system involves the various ways of evaluation, selection and matching them to
produce individual having desired genetic traits in breed or species. Example: Nucleus
Breeding System
➢A breeding system encompasses both the mating system and the selection process.
1. Mating System
•Refers to how animals are paired or mated to achieve specific breeding objectives.
•Common types include Inbreeding, Outbreeding, Crossbreeding, Linebreeding
2. Selection
•Involves choosing which animals to breed based on desirable traits.
•Types of selection: Natural Selection and Artificial Selection
Boby Basnet/Assistant Professor 117

Nucleus Breeding System
System in which a breed is structured in such a way that all the
animals are not allowed to make contribution for genetic
improvement but very few are given thisopportunity
These animals are recorded for large no. of traits and actually
constituting the nucleus herd ex. milk yield ,body wt. , milk fat
etc.
BOBY BASNET/ASSISTANT PROFESSOR 118

Need of NBS
The rate of genetic improvement through conventional breeding program viz.
selection and mating system had been low in developing countries like Nepal.
Nonavailability
of sire with
high genetic
merit in
required no.
Poor spread of
AI due to lack
of infrastructure
Small size of
farmers herd
High cost of
data recording
BOBY BASNET/ASSISTANT PROFESSOR 119

Types of NBS
NBS
ONBS CNBS
BOBY BASNET/ASSISTANT PROFESSOR 120

Closed nucleus breeding system
❑In this system one way gene flow only with the
direction from top to down herds i.e. Nucleus→→
Multiplier→ commercial/village herds.
❑The improvement is made in nucleus herd and passed
on to multiplier and then to the commercialherds.
❑Mainly used in pigs and poultry to avoid the risk of
introducing diseasesinthenucleus flock
BOBY BASNET/ASSISTANT PROFESSOR 121

1.Nucleus tier/herd : Nucleus tier consists of elite breeders ('seed stock'/'stud")
who are self- contained as they produce their own male and female
replacements. It consist of 10 -15 % breed population.
2.Multiplier tier/ herd: This is constituted by about 30 -40 % of breed
population. Their main aim is to procure improved stock from elite breeders
and to produce or multiply the breeding stock in large numbers to meet
demands of commercial tiersbelowthem.
3.Commercial tier: It consists of commercial producers who are primarily
involved in production of milk, meat, eggs or fiber. It has 40 -60 % of breed
population
BOBY BASNET/ASSISTANT PROFESSOR 122

Open nucleus breeding system
➢In this system, the gene flow is both ways downward and upward.
➢The ONBS is used to overcome one of the most serious
limitations of CNBS which is lack of transfer of genetically
superior animals to upper tiers.
➢It reduces the rate of inbreeding in the nucleus herd and increases
the genetic progress because the superior animals are also
available with farmers.
➢Mostly used in cattle, buffalo,andsheep.
➢If higher performance of lower herd is due to their superior
genetic merit ,it would be of great use of great use to transfer such
superior animals into a higher herd.
BOBY BASNET/ASSISTANT PROFESSOR 123

Important Steps
➢Genetically superior animals from
different herds are brought together to form
a nucleus the average genetic merit of
nucleus would be far greater than of any of
the contributing herds.
➢Once a nucleus is established, a proper
system of recording of performance and
selection is implemented.
➢ The best males are kept for breeding in the
nucleus while other selected males given to
the base herds for breeding
BOBY BASNET/ASSISTANT PROFESSOR 124

Advantage of Nucleus Breeding System
1.Accelerated genetic improvement.
2.Efficient use of resources.
3.Centralized testing and selection.
4.Dissemination of superior genetics.
5.Integration with advanced techniques like AI and ET.
6.Easier disease management and biosecurity.
7.Customization for specific breeding goals.
8.Applicability in diverse regions and conditions.
9.Preservation of genetic diversity.
10.Increased productivity and profitability.
BOBY BASNET/ASSISTANT PROFESSOR 125

Conclusion
1.Closed Nucleus Breeding System (CNBS):
1.No external genetic material is introduced into the nucleus herd after it is established.
2.Decisions regarding selection and mating are controlled entirely by the breeding organization.
2.Merits:
1.Reduced risk of disease introduction.
2.Easier to maintain pedigree records due to smaller herd size.
3.Suitable for poultry and pigs to protect the herd from diseases.
4.Cost-effective, especially before the advent of advanced technologies.
3.Demerits:
1.Inbreeding becomes a concern over generations.
2.Slower genetic progress due to the limited genetic pool.
3.May not reflect true genetic performance due to environmental factors.
4.Restricted flow of genes from commercial herds to the nucleus.
Boby Basnet/Assistant Professor 126

1. Open Nucleus Breeding System (ONBS):
•Allows genetic material from commercial or lower-tier herds to enter the nucleus herd if
their breeding value is higher.
•Relies heavily on modern techniques like artificial insemination, in vitro fertilization, and
embryo transfer for genetic dissemination.
2. Merits:
•Higher genetic progress due to the ability to introduce superior genes from the production
population.
•Lower risk of inbreeding.
•Faster dissemination of improved genes to the commercial herds.
•Maintains greater genetic diversity.
3. Demerits:
•Requires accurate performance records from lower tiers to avoid introducing inferior genes.
•Larger herd sizes are necessary for effective selection and progress.
•Significant infrastructure investment is required for data recording and evaluation.
•Long-term planning and commitment are essential.
Boby Basnet/Assistant Professor 127

Comparison of CNBS and ONBS
Feature
Closed Nucleus Breeding
System (CNBS)
Open Nucleus Breeding
System (ONBS)
Gene Flow Restricted to nucleus herd
Open to superior genes from
commercial herds
Inbreeding Risk Higher Lower
Genetic Progress Slower Faster
Diversity Limited Maintained
Infrastructure NeedsLower Higher
Disease Risk Minimal
Higher due to gene flow
from outside
Boby Basnet/Assistant Professor 128

Selection
Process in which certain individuals in a population are preferred to
others to produce the next generation.
It is the basic tool available to the breeder for livestock improvement
because it changes the gene frequency to better fit individuals for a
particular trait.
The changes obtained by selection are of permanent nature unless
counter selection in the opposite direction begins.
Boby Basnet/Assistant Professor 129

Genetic Effect of Selection
➢Selection does not create new genes, but it increases the
frequency of desirable genes and decreases the frequency of
undesirable genes in population.
➢If the frequency of desirable gene is increased the proportion of
individual homozygous for the desirable gene is also increased.
Boby Basnet/Assistant Professor 130

Principles of Selection/Selection Parameters
1.Accuracy of selection
2.Selection differential
3.Selection intensity
4.Generation interval
5.Genetic Gain/Response to Selection
Boby Basnet/Assistant Professor 131

Accuracy of Selection
•Definition: The correlation between the true breeding value (BV) of an individual and the
estimated breeding value (EBV).
•Key Influencers:
•Heritability of the trait: Higher heritability leads to higher accuracy.
•Data quality and quantity: Accurate records and large data sets improve accuracy.
•Selection method: BLUP (Best Linear Unbiased Prediction) increases precision.
•Importance: Higher accuracy ensures that selected individuals are truly genetically superior
Boby Basnet/Assistant Professor 132

Selection Differential (SD)
•Definition: The difference between the mean trait value of selected
individuals and the population mean. SD= x̄ selected- x̄ population
•Example: If the average milk yield in a population is 20 liters and the
selected individuals average 25 liters, the SD is 5 liters.
•Significance: Represents the genetic potential that selected individuals bring
to the next generation.
Boby Basnet/Assistant Professor 133

Selection Intensity (i)
•Definition: A standardized measure of how strict the selection process is.
i=SelectionDifferential/StandardDeviationoftheTraitinthePopulation
•Factors affecting intensity:
•Proportion of individuals selected: Fewer individuals selected lead to higher
intensity.
•Population size: Larger populations allow stricter selection.
•Impact: High selection intensity accelerates genetic improvement
Boby Basnet/Assistant Professor 134

Generation Interval (L)
•Definition: The average time between the birth of parents and the birth of their
offspring.
•Key Factors:
•Species: Longer-lived species have longer intervals.
•Breeding management: Early maturity and reproductive management can
reduce generation interval.
•Formula: GeneticGain∝1/L
•Importance: Shorter generation intervals speed up genetic progress.
Boby Basnet/Assistant Professor 135

Genetic Gain / Response to Selection (RRR)
•Definition: The improvement in a trait achieved per generation through selection.
•Formula: R=h²×SDR Where:
h²= Heritability of the trait.
SD = Selection differential.
Factors affecting genetic gain:
•Heritability (h²): Higher heritability results in faster progress.
•Selection differential and intensity: Greater values improve gain.
•Generation interval: Shorter intervals enhance response.
Boby Basnet/Assistant Professor 136

Basis of Selection
1.Selection based on individuality or individual performance
2.Selection based on pedigree record
3.Selection based on progeny test
4.Selection based of collateral relatives
Boby Basnet/Assistant Professor 137

Selection based on Individuality
➢For selection, an animal is kept or rejected for breeding purposes on the basis of its own
phenotype for a particular trait, or traits.
➢The progress made in selection depends upon how closely the genotype is correlated
with the phenotype.
➢Sometimes this correlation is high, but there are times when it is low.
➢The phenotype of the individual varies through out its life because of environmental
effects or the interaction between its genotype and environment.
Boby Basnet/Assistant Professor 138

Advantage
➢Easy availability of information for breeding.
➢It can be applied before progeny test and do not require pedigree information.
➢This gives direct estimate of breeding value and not based on relative hence it is more
accurate.
➢Highly heritable traits are selected.
Disadvantages
➢When traits are expressed by an individual it is not always applicable.
➢For example : Milk production and egg production in female.
➢When heritability is low individual is poor indicator of breeding value.
➢It is not applicable in later life generation character which is only expressed in later life of
an individual. For example: Cancer eye.
Boby Basnet/Assistant Professor 139

Selection based on Pedigrees
➢A pedigree is a record of an individual’s ancestors related to it through its parents.
➢Little pedigree has been indicated as to their phenotypic and genotypic merit.
➢More recently, data to indicate the phenotypic merit of ancestors are being included in
pedigrees.
➢These pedigrees are called performance pedigrees.
Types
1. Dirty pedigree: Individual having ancestor which produces some undesirable traits.
2. Clean pedigree: Ancestor does not have undesirable traits; low frequency of
undesirable traits.
Boby Basnet/Assistant Professor 140

Advantages
➢It is cheaper basis of selection.
➢It is useful when animal are selected at early stage.
➢Useful for selection of both sexes for sex limited traits. Example bull can be selected
on the milk record of female relatives.
➢Useful for traits which are expressed in later stage. Example: Cancereye.
➢Can be use as goal for preliminary selection of sires for progeny testing.
Disadvantages
➢There is lower accuracy to an individual selection.
➢Progeny of favored parents are often environmental unfavored.
➢Superiority of pedigree due to environment.
➢Relatives makes record on different on environment so selection may not be
effective.
Boby Basnet/Assistant Professor 141

Selection based on Progeny Tests
Selection on this basis means that the breeder decides to keep or cull a
sire or dam based on the average merit of their offspring as compared to
the average merit of the progeny of current sires and dams.
Progeny tests may be used in selection for both qualitative and
quantitative traits.
Probably the most effective use of progeny tests in selection for
qualitative traits is to determine if an individual of the dominant
phenotype is homozygous or heterozygous.
Boby Basnet/Assistant Professor 142

Advantages
➢It is useful for sex limited traits. Example: Milk and egg production.
➢More accurate than other (pedigree) method of selection.
➢It is useful for identification of carrier individual for harmful genes.
Disadvantages
➢Long generation interval is required to achieve a particular level of genetic gain.
➢Requires high reproductive rate for more accuracy.
➢Only few candidate can be tested thus selection intensity is low.
Boby Basnet/Assistant Professor 143

Selection based on Collateral Relatives
Collateral relatives are those not directly related to an individual as ancestors or progeny.
Thus, they are the individual’s brothers, sisters, cousins, uncles, aunts, etc.
The more closely they are related to the individual in question, the more valuable is the
information they can supply for selection purposes.
Information on collateral relatives is used in selecting dairy bulls, since milk production can
be measured only in cows even though the bull possesses and transmits genes for milk
production to his offspring.
Records on collateral relatives can also be used in the selection of poultry for egg and meat
production and for all-or-none traits such as mortality, disease resistance, or fertility.
Boby Basnet/Assistant Professor 144

Advantages:
➢Useful for sex limited characters.
➢When character are carcass trait and threshold trait like twinning in cattle, disease
resistant.
➢Most effective when within the family member genotype relationship is higher and
phenotype relation is small.
➢For traits of low heritability.
Disadvantages:
➢It is costly.
➢Requires larger breeding and testing space.
➢Results in inbreeding and limit genetic diversity.
➢The family can only be applied in species with high reproductive rates to get large
family size.
Boby Basnet/Assistant Professor 145

Methods of selection
Selection
Natural Artificial
Tandem method Independent culling labelsSelection index
Boby Basnet/Assistant Professor 146

Natural Selection
➢In Nature, the main force responsible for selection is the survival for fittest in
a particular environment.
➢Thus, there is a teaching of nature to select against the weaker ones and only
the stronger survive to reproduce the species.
➢Natural selection is very complicated process, and many factors determine
the proportion of individuals that will reproduce. Those factors are:
•Difference in mortality of the individuals in the population.
•The degree of sexual activity itself
•Difference in the degree of fertility of individuals in the population
Boby Basnet/Assistant Professor 147

Artificial Selection
It is defined as the efforts of man to increase the frequency of desirable
genes or combination of genes in his/her herd or flock by locating and
saving for the breeding purpose.
While selection animals, breeders must have knowledge or information
about the quality of each animal and for this purpose an estimation of
animals’ commercial and breeding value should be obtained.
Boby Basnet/Assistant Professor 148

Tandem Selection Method
•Breeder selects and improves only one trait at a time until it reaches an acceptable level,
and then he shift to another and so on for a third.
•A breeding method where traits are selected one at a time in successive generations.
•Once a desired level is achieved for one trait, the next trait is targeted for improvement.
•Identify the traits to be improved.
•Select individuals for the first trait and breed them until the desired improvement is
reached.
•Shift the focus to the next trait, repeating the process.
Boby Basnet/Assistant Professor 149

Advantages:
1.Simplicity: Easy to implement as focus is on one trait at a time.
2.Clarity: Progress in individual traits can be easily measured.
Limitations:
1.Time-Consuming: Improving multiple traits takes several generations.
2.Low Efficiency: Not suitable for programs requiring simultaneous improvement
of traits.
3.Correlation Issues:
1.Positively correlated traits: Suitable.
2.Negatively correlated traits: Can lead to regression in previous traits (e.g.,
milk yield vs. fat percentage).
4.Maintenance Difficulty: Maintaining improvement in earlier traits while
progressing in others is challenging.
Boby Basnet/Assistant Professor 150

Independent Culling Method
➢In this method, selection may be practiced for two or more traits at a time.
➢But for each trait, a minimum standard (culling level) is set, so that every animal must
meet the minimum standards to be selected for the breeding purposes.
➢The failure to meet the minimum standard for any one trait makes the animal to be
rejected.
➢Therefore, in actual practice, it is possible to cull some genetically very superior
animal when this method is used.
Boby Basnet/Assistant Professor 151

Based on standard set-in above Cow 1 is selected instead of low milk yield.
Boby Basnet/Assistant Professor 152

Selection Index
•It involves separate determination of value for each of the traits selected and addition of
these values to give at total score for all the traits.
•The animals with highest scores are then kept for breeding purpose.
•This is more efficient than independent culling levels as it allows individuals, that are
superior in some traits to be saved for breeding even though they are slightly deficient in
one or more of the other trait
•In dairy cattle, milk production is the most important economic trait, whereas the
reproductive efficiency that is also important, may not be as important in magnitude as
milk production.
•Hence, higher economic value should be given to milk production and correspondingly
lower economic value to the reproductive efficiency.
Boby Basnet/Assistant Professor 153

•I=b1X1+b2X2+b3X3+……..+bnXn
Where,
I- Index value or genetic prediction.
n- Number of traits of information.
b1 to bn- Coefficients obtained based on the relative importance of heritability of each trait
and genetic relationships of the traits concerned.
X1 to Xn- Measurement of each of the traits incorporated (Phenotypic values).
Boby Basnet/Assistant Professor 154

6. Traits of Economic Importance
in Livestock and Poultry
Boby Basnet/Assistant Professor
Animal Science
Boby Basnet/Assistant Professor 155

TRAITS
➢A trait is a distinguishing phenotypic characteristic, typically belong to an individual.
➢In practice this means anything you can record or measure on an individual.
a.Threshold traits: A threshold trait is a trait which is inherited quantitatively but
expressed qualitatively. Example: Coat colour in animal.
b.Sex Linked Trait: Traits in animals that are related to their sex chromosomes. Eg:
rapid and slow feathering.
c.Sex Limited Traits: Trait which are expressed in one sex (either male or female). Eg:
Egg production-females only.
Boby Basnet/Assistant Professor 156

TYPES OF TRAITS
1.Qualitative: The characters controlled by one or few pairs of gene, show
discontinuous variation i.e., those in which variations fall into a few clearly
defined classes & least influenced by environment. Example: comb type, plumage
shank color, plumage pattern, curling of feathers. Almost all the traits whose
inheritance is well-known are in the qualitative class.
2.Quantitative: Controlled by many pairs of gene, which show continuous
variation, i.e., there are small gradations in the expression from one extreme to the
other and largely influenced by environmental factors. Traits of economic values
are mostly quantitative traits. Examples: Bodyweight, Egg production, Fertility,
hatchability etc. These traits are characterized by Polygenic Inheritance (genes
concerned are at many loci) and have a large environmental effects.
Boby Basnet/Assistant Professor 157

SELECTION CONCERNS FIVE TYPE OF TRAITS
➢Traits in farm animals can be categorized into five features namely reproductive, production,
quality, aesthetic and behavioral traits.
1.Reproductive traits are also referred as fitness traits that are normally concerned with
reproduction and viability. Examples of such traits are litter size, conception rate, calving
interval, gestation length, survival ability, etc.
2.Production traits include milk yield, growth rate, feed efficiency, weaning weight, wool
yield, egg production etc.
3.Quality traits are referred to meat and milk, wool and eggs quality. Meat quality refers to
carcass composition, back fat thickness in pig, eye muscle area in all carcass, meat quality,
milk fat percentage.
4.Aesthetic traits are usually features of a more aesthetic nature were personal preference in
important. Examples include coat colour, coat type, udder shape, physical appearance, horn
shape, etc.
5.Behavioral traits are those involved in animal welfare. Example includes docility of pet dogs,
bulls for ploughing, horse for riding, etc.
Boby Basnet/Assistant Professor 158

DAIRY CATTLE/BUFFALO TRAITS
1.Reproductive Traits-Age at first calving, Services per conception, service
period, calving interval, twinning, dystocia.
2.Production traits: Milk yield per lactation
3.Quality traits: Milk fat composition, Milk protein composition
4.Aesthetic traits: Polled, Soft skin
5.Behavioral traits: Temperament
Boby Basnet/Assistant Professor 159

SHEEP/GOAT TRAITS
1.Reproductive Traits: Age at first mating, litters per year.
2.Production Traits: Fleece diameter, fleece weight,
3.Quality traits: Medullation, killing out per cent
4.Aesthetic traits: Polled
5.Behavioral traits: Temperament
Boby Basnet/Assistant Professor 160

PIG TRAITS
1.Reproductive Traits: Litter size, Litter per year, Survival ability.
2.Production traits: Weaning weight, Slaughter weight, Age at slaughter
3.Quality traits: Lean carcass, Dressing percentage, Fat depth
4.Aesthetic traits: Skin colour, Teat numbers
5.Behavioral traits: Temperament
Boby Basnet/Assistant Professor 161

HORSE TRAITS
1.Reproductive: Age at first foaling, Longevity
2.Quality: Carrying capacity, Surefooted, Body conformation, Extremities,
Disease resistance, Adaptability
3.Aesthetic: Coat color, Body marking
4.Behavioral: Behavior/ Vices, Strength, Vigor, Stamina, Gait
Boby Basnet/Assistant Professor 162

POULTRY TRAITS
1.Reproductive: Age, Fertility, Disorder
2.Production: Egg size, Number, Laying period
3.Quality: Growth, Flavor and taste, Shell color
4.Behavioral: Broodiness
5.Aesthetic: Feather color, Fighting, Body conformation
Boby Basnet/Assistant Professor 163

ECONOMIC TRAITS OF CATTLE AND BUFFALOES
1.Reproductive Traits:
✓Age at first service
✓Age at first puberty
✓Service per conception
✓Calving interval
✓Post partum estrus
2. Milk and butter fat production Traits
✓Lactation milk yield
✓Butter fat yield
✓Butter fat% age
✓Solid not fat
✓Persistency of lactation
✓Peak milk yield etc.
Boby Basnet/Assistant Professor 164

ECONOMIC TRAITS OF SHEEP AND GOATS
1. Economic traits
➢Age at maturity, Age at conception, Service per conception, kidding/lambing interval,
Post partum estrus, Number of kids/lambs per kidding/lambing.
2. Production traits
➢Birth weight, Weaning weight, Number of kids/kidding, Number of kids/lambs weaned
per doe/ewe, Post weaning weight, Clean fleece weight, Grease fleece weight, Staple
length (it is measured in a crimped/waviness condition and is a length of wool), Fiber
diameter
Boby Basnet/Assistant Professor 165

ECONOMIC TRAITS OF POULTRY
1.Growth: Body weight, FCR, growth rate.
2.Egg: Number, weight, shell quality, age at first egg.
3.Reproduction: Hatchability, fertility, reduced broodiness.
4.Meat: Dressing %, breast yield, low fat.
5.Feed: Intake, nutrient efficiency.
6.Health: Disease resistance, low mortality.
7.Behavior: Adaptability, calmness.
8.Market: Appearance, taste, texture.
Boby Basnet/Assistant Professor 166

Breeding Plan
•A breeding plan is a structured and systematic approach to improve the genetic
potential of a population of animals through planned mating and selection.
•It involves setting clear goals, selecting desirable traits, identifying suitable
breeding methods, and implementing strategies to achieve long-term genetic
improvement while ensuring sustainability, productivity, and profitability.
Boby Basnet/Assistant Professor 167

Key Components of a Breeding Plan
Clear Objectives: Define the specific goals of the breeding program, such as improving
milk yield, growth rate, disease resistance, or reproductive performance.
Selection of Breed: Identify and choose breeds or genetic lines that align with
production goals and are suitable for the environment and management system.
Trait Prioritization: Determine which traits are most important for improvement,
focusing on economically significant and heritable traits.
Animal Selection: Choose the best-performing animals (based on records and
evaluation) to serve as parents for the next generation.
Boby Basnet/Assistant Professor 168

5.Mating Strategies: Design mating systems to achieve the desired genetic outcomes,
including pure breeding, crossbreeding, or composite breeding
6.Data Collection and Recording: Maintain accurate records of performance, health,
reproduction, and pedigree to guide selection decisions and track progress.
7.Monitoring and Evaluation: Continuously assess the impact of the breeding plan on
production and adjust strategies as needed.
8.Replacement Strategy: Develop a plan to replace older or less productive animals with
genetically superior young stock to maintain herd quality and productivity
Boby Basnet/Assistant Professor 169

7. Mating system: Inbreeding and Out breeding
Boby Basnet/Assistant Professor
Animal Science
Boby Basnet/Assistant Professor 170

Mating System
➢Mating system is a way in which organisms develop and maintain reproductive
partnership.
➢A mating system is a way in which a group is structured in relation to sexual
behavior.
➢The precise meaning depends upon the context.
➢With respect to higher animals, the term describes which males mate with which
females, under which circumstances.
➢The purpose of mating is to gain genetic superiority and hybrid vigor.
Boby Basnet/Assistant Professor 171

Types of mating system
Boby Basnet/Assistant Professor 172

A. Inbreeding
•Inbreeding is defined as the mating between the individuals which are related to
each other more closely than the average relationship between all individuals in
the population.
•Inbreeding involves the mating of related individuals within 4 to 6 generations.
•Requires a careful program of selection and culling.
•Used most often by Universities for experimental work and Seed stock producers
that provide animals for cross breeding herds.
Boby Basnet/Assistant Professor 173

Types of Inbreeding
1. Close Breeding
✓Mating between more close relatives.
✓Eg: Full brother-sister, parents-offspring
2. Line Breeding
✓Mating within an ancestral line.
✓Eg: Half brother X Half sister, Grandsire X Grand daughter, Grand Son X Grand
Dam, Great grand sire X Great grand daughter, Great grand-son X Great grand-dam,
Cousin etc.
Boby Basnet/Assistant Professor 174

Boby Basnet/Assistant Professor 175

Genetic effect of Inbreeding
✓Inbreeding doesn’t create new genes, and usually, change the frequency of genes.
✓It merely increases homozygosity & decreases heterozygosity in a population regardless
of the kind of gene action involved.
Uses of Inbreeding
✓It is used in maintaining seed stock.
✓Makes the stock more homozygous, thus adds in selection. Usually, recessive
homozygous express the undesirable characters and can be culled easily.
✓Increases prepotency (ability of an individual or strain to transmit its characters to
offspring because of homozygosity).
✓Increases total variability of population.
✓Fixes characters in the population.
✓It is the surest way of testing genetic worth of individual.
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Outward effect of Inbreeding
✓Decreases growth rate and mature body weight.
✓Increases embryo mortality.
✓Reduces reproductive efficiency.
✓Decrease in vigor of the animals.
✓Decrease in production traits.
✓Appear lethal genes/detrimental genes and other abnormalities in progenies.
✓Decreases in adaptability in adverse environment.
✓Maintain both desired and undesired character in a progeny.
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B. Outbreeding
➢The mating of animals not as closely related as the average of the population.
➢In this method it is possible to breed desirable type of animal with a less desirable type and then to
increase degree of desirable traits.
➢Mating of unrelated, female's individuals within the same breed. Example: Jersey (M) × Jersey (F)
Types of outbreeding
1. Pure breeding/out crossing
➢Mating of unrelated, pure males and female livestock animals within a same breed or type.
Jersey M x Jersey F = Jersey M/F
Advantages
➢New and high yielding genes can be introduced into the population.
➢Can produce a hybrid of superior vigor and value.
➢Best method for genetic improvement within flock
Limitations
➢Traits with low heritability could not be improved through pure breeding.
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2. Cross breeding
➢Mating between the unrelated individuals of different breeds or strains i.e.
generally used for the production of new breed.
➢Therearefollowingtypesofcrossbreeding:
a.Twobreedcross
b.Crisscrossing/Repeatedbackcross
c.Rotational/3-breed/Triplecrossing
d.Backcrossing
e.Testcrossing
f.Topcrossing
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a. Two breed cross
➢Pure bred animals of 2 different breeds are used for mating and purity of the
parental breeds is not altered.
➢Example: Jersey × Red Sindhi = Jersindhi
b. Criss cross/Repeated backcross
➢Crossbred F1 females are kept for breeding and are mated with the unrelated males from
one or the other of the two original pure breeds used in the two breeds cross alternatively
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c. Rotational/3-breed/triple crossing
➢Three breeds are crossed in a rotational manner.
➢Males from each of the breed involved in mating program are used in succession on
crossbred females.
➢The first cross animal(F1) is mated to an animal of a third breed like AB with C.
➢This results in full utilization of maternal heterosis because the dam is 100% heterozygous
being crossbred.
A x B
AB x C
ABC
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d. Back Crossing: Mating of F1 crossbred female back to one of its parental breeds (either
dominant or recessive).
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Advantages of cross breeding
➢Valuable means of introducing desirable characters into a breed.
➢Crossbred animal usually exhibit an accelerated growth and vigor.
➢New breeds with increased producing ability can be produced.
Disadvantages of crossbreeding
➢Breeding merit of crossbred animals may be reduced because of heterozygous nature
of their genetic composition.
➢Requires maintenance of animals/parents of two or more pure breeds, that increases
the investment.
➢Males of higher exotic bloods are not suitable for agriculture purpose.
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3. Upgrading/Grading up
•Mating of parental sires of a breed with non descript local females and their
offspring for generation after generation in order to improve the productivity.
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Advantages
➢It affects rapid improvement of indigenous animals thrived small no. of males of
improved breed.
➢It is the best method to improve the local cattle of rural areas.
➢It helps to prove the quality of bull which consequently increase the market value.
➢It is good beginning for new breeder who can gradually change over to pure breed
system.
Limitations
➢Pure breeds are not always better than the indigenous animals.
➢Pure breed stocks are not always thrived well in all set of environment.
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Hybridization
•System of mating in which animals of two different species are mated.
•Mating of male and female or two different species is known as hybridization or
species hybridization.
•Example: Liger= Lion+Tiger, Cattlo= Cattle + Buffalo
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Advantages
➢Increased vigor in the progeny and hardy by nature.
➢Increased production.
➢Increased growth rate of progenies than the parents.
➢More disease resistant than parents.
➢Better adaptability in adverse environmental condition.
➢More working capacity.
➢Increased size and body weight
Limitations
➢One of the most important limitation of hybridization is that, in most cases, either they are impotent or
sterile and hence are unable to reproduce due to: Abnormal chromosomal separation and Lack of
gametogenesis: Incapability of gamete formation for fertilization
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8. Genetic resistance to diseases and
parasites.
Boby Basnet/Assistant Professor
Animal Science
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INTRODUCTION
✓Genetic resistance to diseases and parasites refers to an organism's inherent ability to resist or tolerate
infections caused by pathogens or parasites. This resistance is primarily determined by the organism’s
genetic makeup and can involve multiple defense mechanisms.
Examples of Genetic Resistance in Livestock:
1.Cattle: African indigenous breeds show resistance to trypanosomiasis.
2.Sheep: Gulf Coast Native sheep are naturally resistant to internal parasites like Barber Pole Worm.
3.Pigs: Certain pig breeds exhibit resistance to diseases like Porcine Reproductive and Respiratory
Syndrome (PRRS).
4.Poultry: Some indigenous chicken breeds have genetic resistance to Newcastle disease.
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196

Genetic Resistance in Livestock (Factors)
Innate Immune System Efficiency: Some livestock breeds have a naturally strong immune
system that effectively identifies and eliminates pathogens.
Physical Barriers: Traits such as thicker skin, dense hair coats, or specialized mucosal
linings help prevent pathogen entry.
Antimicrobial Compound Production: Certain breeds produce natural antimicrobial
substances that inhibit the growth of bacteria, viruses, and parasites.
Behavioral Adaptations: Some animals exhibit behaviors that reduce parasite exposure, such as
grooming or selective grazing.
Cellular and Molecular Defense: Activation of specific genes upon pathogen recognition can
enhance immune responses, such as increased production of antibodies or resistance proteins.
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Mechanism of disease
resistance
1.Resistance
2.Avoidance
3.Tolerance
4.Immunity
5.Hypersensitivity
6.Genomic interaction
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1.Resistance
The ability of an organism to exclude or overcome completely or in
some degree the effect of a pathogen or other damaging factor.
Ability of host to restrict or even prevent the production of disease
symptoms on invasion of pathogen due to presence of resistance genes.
There are 2 types of resistance:
a. Vertical resistance
b. Horizontal resistance
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a.Vertical Resistance (Specific Resistance)
➢Vertical resistance is a type of resistance controlled by a single or a few major genes,
providing strong but often pathogen-specific protection. It follows the gene-for-gene
interaction model, where resistance depends on the presence of specific resistance (R)
genes in the host and corresponding a virulence genes in the pathogen.
➢Controlled by one or a few major genes.
➢Genes are easily transferred from one genotype to another through selective breeding.
➢Provides strong, pathogen-specific immunity but can be overcome if the pathogen
evolves.
➢Common in livestock species such as cattle, pigs, and chickens, were certain breeds
exhibit resistance to specific diseases.
➢ Examples: Some cattle breeds are resistant to bovine respiratory syncytial virus (BRSV)
and bovine viral diarrhea virus (BVDV) due to specific genetic traits.
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Gene-for-gene
interaction model
•The gene-for-gene model isa concept that
describes how genes interact with each other
and with other factors to influence traits in
animals.This model can be used to study how
genes affect behavior, disease, and other
traits.
201

b. Horizontal Resistance:
➢Horizontal resistance is a type of resistance controlled by multiple genes, each contributing
minor effects. It provides broad-spectrum protection against a wide range of pathogens but
is generally less specific than vertical resistance.
➢Controlled by multiple genes, each with minor effects.
➢Challenging to transfer between genotypes.
➢Individual genes are difficult to identify.
➢Varies among individuals within a population and is influenced by genetic and
environmental factors.
➢The skin serves as a physical barrier against microorganisms, while mucous membranes
secrete antimicrobial substances to prevent infections.
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Vertical Resistance Vs Horizontal Resistance
Vertical Resistance Horizontal Resistance
Oligogenic resistance Polygenic resistance
Race specific Race non-specific
Qualitative in nature Quantitative in nature
Less influenced by environment Highly influenced
Controlled by one or few genes Controlled by many genes
Highly efficient Less efficient
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2. Avoidance
Avoidance refers to the behaviors or adaptations that enable animals to avoid or minimize
encounters with potential threats, such as predators, parasites, or dangerous environments.
Examples: Burrowing Animals like groundhogs and rabbits dig burrows to create
underground tunnels and chambers where they can hide from predators.
Nocturnal behavior: Some animals are primarily active during the night (nocturnal) rather
than during the day (diurnal). This helps them avoid encounters with diurnal predators or
reduces competition for resources.
Warning signals: Certain animals have developed warning signals, such as bright colors or
specific vocalizations, that indicate their toxicity or unpalatability.
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204

3. Tolerance
Tolerance in animals refers to their ability to withstand or endure adverse conditions, stressors,
or diseases without significant negative effects on their health, welfare, or performance.
For example, Brahman cattle have developed efficient heat dissipation mechanisms, such as
increased sweating, which helps them regulate body temperature in hot environments.
Additionally, certain pig breeds exhibit higher tolerance to poor-quality feed, maintaining
growth and reproduction despite dietary limitations.
These tolerance traits are crucial for sustainable livestock farming, especially in regions with
extreme climates or limited resources.
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4. Immunity
Immunity in animals refers to their ability to resist or defend against pathogens such as
bacteria, viruses, parasites, and fungi, as well as harmful substances or toxins.
It can be classified into two main types: innate immunity, which provides immediate,
broad-spectrum protection, and acquired immunity, which develops after exposure to
specific pathogens, leading to immune memory.
An example of natural immunity is seen in wild waterfowl, such as ducks, geese, which
exhibit remarkable resistance to avian influenza (bird flu).
While domestic poultry often experience severe illness and high mortality rates from
certain strains of the virus, duck and geese can carry and spread the virus with minimal
symptoms, highlighting their evolved immune resilience.
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206

5. Hypersensitivity
Hypersensitivity in animals refers to an exaggerated or abnormal immune response to
harmless substances or antigens, resulting in tissue damage, inflammation, and clinical
signs of allergy.
A common example is atopic dermatitis, also known as atopy or allergic dermatitis, in
dogs.
This condition is triggered by environmental allergens such as pollen, dust mites, mold
spores, and certain foods, leading to an overactive immune reaction.
Affected dogs often exhibit symptoms such as persistent itching (pruritus), excessive
scratching, rubbing, licking, chewing, and recurrent skin infections, which can significantly
impact their comfort and well-being.
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6. Genomic Interaction
Genome interaction refers to the complex interplay between genes, proteins, and
environmental factors that regulate biological functions that are crucial for
understanding gene expression, inheritance patterns, disease mechanisms, and
evolutionary processes.
These interactions help determine how genes regulate each other, impact an animal’s
characteristics, and contribute to overall health and performance.
Understanding genomic interactions is essential in animal breeding, as it allows for the
selection of desirable traits such as disease resistance, productivity, and adaptability.
By leveraging genomic information, scientists and breeders can enhance genetic
improvement programs, leading to healthier and more efficient livestock populations.
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Genomic Interaction
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Importance of Genetic Resistance in Agriculture and
Animal Husbandry
1.Reduced Dependency on Chemical Treatments: Genetic resistance decreases reliance on chemical treatments,
such as pesticides and antibiotics, for disease and parasite control. By selecting resistant livestock breeds, farmers
can minimize chemical inputs, reducing environmental impact and lowering production costs.
2.Improved Animal Health and Welfare: Genetic resistance enhances animal health by reducing disease
incidence and severity. Resistant animals are less susceptible to infections, leading to lower mortality rates,
reduced suffering, and overall improved well-being.
3.Enhanced Productivity and Efficiency: Disease-resistant crops and livestock allocate fewer resources to
fighting infections, leading to higher productivity. Healthy animals utilize nutrients more efficiently, improving
feed conversion rates and increasing yields of meat, milk, and eggs, thereby boosting farm profitability.
4.Sustainable Agriculture Practices: Genetic resistance supports sustainable farming by promoting natural
disease and pest control mechanisms. Sustainable practices prioritize biological controls, cultural management
techniques, and the use of resistant breeds to minimize environmental impact and maintain ecosystem health.
5.Resilience to Environmental Stresses: Resistant livestock can better withstand environmental challenges such
as extreme weather, drought, and pathogens. This resilience ensures continuous production and strengthens food
security amid changing climatic conditions.
6.Long-Term Economic Benefits: Investing in genetic resistance reduces the risk of production losses due to
disease outbreaks, leading to long-term economic stability for farmers. Resilient agricultural systems adapt more
effectively to evolving challenges and market demands, ensuring sustainable and profitable farming operations.
210

9. Transgenic animal and their
production
Boby Basnet/Assistant Professor
Animal Science
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Transgenic Animal
•Transgenic animals are organisms that have
foreign genes deliberately inserted into their
genome using genetic engineering
techniques.
•These genes can originate from other species
and are introduced to give the animal
desirable traits, such as disease resistance,
faster growth, or enhanced productivity.
•This method is done to improve the genetic
traits of the target animal.
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Techniques for Producing Transgenic Animals
Techniques for Producing Transgenic Animals
1. Microinjection of DNA: Foreign DNA is directly injected into the nucleus of a
fertilized egg.
2. Retrovirus-Mediated Gene Transfer: Viruses are used to transfer foreign genes
into the animal’s genome.
3. Embryonic Stem Cell Manipulation: Modified stem cells are inserted into an
embryo to develop into a transgenic organism.
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Microinjection of DNA
•This method involves the direct microinjection of a desired gene into the
pronucleus.
•The manipulated fertilized ovum is transferred into the recipient female.
•This method is applicable to a wide variety of species.
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Embryonic stem cell mediated gene transfer
•This method involves prior insertion of the desired gene but homologous
recombination into an invitro culture of embryonic stem (ES) cells.
•These cells are then incorporated into the inner cell mass of an embryo at the
blastocyst stage of development.
•The blastocyst is transferred into the recipient female.
•The result is a chimeric animal.
•This method is used for gene inactivation (knock out).
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Retro virus mediated gene transfer
•This method involves gene transfer by means of a viral vector such as
retrovirus.
•Since retrovirus could infect the host cell, they are used as vectors to
transfect the target gene into the animal genome.
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Example of Transgenic Animal
1. Dolly Sheep
•Dolly the sheep was the first mammal to be
cloned from an adult cell. In this, the udder
cells from a 6-year-old Finn Dorset white
sheep were injected into an unfertilized egg of
a Scottish Blackface ewe, which had its
nucleus removed. The cell was made to fuse
by electrical pulses. After the fusion of the
nucleus of the cell with the egg, the resultant
embryo was cultured for six to seven days. It
was then implanted into another Scottish
Blackface ewe which gave birth to the
transgenic sheep, Dolly.
https://www.nms.ac.uk/discover-catalogue/the-story-of-dolly-the-sheep
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Transgenic fish
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Applications of Transgenic Animals
1. Agriculture
✓Faster growth & higher productivity., Disease-resistant livestock, Improved milk quality,
Better feed efficiency.
2. Biomedical & Pharmaceuticals
✓Producing human drugs, Organ transplantation, Gene therapy & disease research.
3. Environment
✓Lower pollution, Bioremediation.
4. Food & Nutrition
✓Healthier animal product., Hypoallergenic milk & eggs.
5. Scientific Research
✓Studying genes & improving animal welfare.
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10. Animal biotechnology and recent advances
in animal biotechnology
Boby Basnet/Assistant Professor
Animal Science
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Animal biotechnology
•Animal biotechnology is a branch of biotechnology that applies molecular biology
techniques to genetically engineer animals, enhancing their suitability for
agricultural, industrial, and pharmaceutical purposes.
•This field has played a significant role in genetic improvement and the
maintenance of genetic diversity in domestic animals.
•Basic animal biotechnologies, such as artificial insemination and embryo transfer,
have been well-established and widely applied as powerful tools for the genetic
enhancement of livestock.
•In particular, the use of sexed semen has become increasingly popular in artificial
insemination techniques, allowing for better control over the sex ratio of offspring.
•Additionally, ongoing efforts are focused on refining technologies that use a
smaller amount of sperm, making the process more efficient and accessible.
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Different methods used in Animal Biotechnology
1.Artificial Insemination (A.I): Artificial
Insemination (A.I) is the introduction of
semen and viable sperm into the female
reproductive tract via artificial means,
typically using an A.I gun. This
technique enhances genetic improvement
and reproductive efficiency in livestock
production.
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2. Multiple Ovulation Embryo Transfer (M.O.E.T)
Multiple Ovulation Embryo Transfer
(M.O.E.T) involves the transfer of a
cultured, 7-day-old embryo into a recipient
female animal of the same species. This
technique maximizes the reproductive
potential of genetically superior females
and accelerates the dissemination of
desirable traits.
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3. Semen and Embryo Cryopreservation (S&EC)
Semen and Embryo Cryopreservation
(S&EC) is a method of preserving semen
or embryos by freezing them to ensure
long-term viability. This technique plays a
crucial role in conserving endangered
species and maintaining genetic diversity.
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4. In-vitro Oocyte Maturation and Fertilization (IVM/IVF)
In-vitro Oocyte Maturation and Fertilization
(IVM/IVF) is the process of fertilizing an ovum by
a spermatozoon outside the body. This advanced
reproductive technology allows for the development
of embryos in a controlled environment before
being transferred to the recipient female.
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5. Sperm Sexing Technology (SST)
Sperm Sexing Technology (SST)
involves sorting spermatozoa
according to their DNA content
using standard flow cytometry
equipment. It enables the
separation of X- and Y-
chromosome-bearing live sperm
cells, allowing for the selection of
offspring sex and improving herd
management strategies.
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6. Cloning
Cloning is the creation of an
organism that is an exact genetic
copy of another organism. This
technology has potential
applications in preserving elite
genetics, producing identical
animals for research, and
conserving endangered species.
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7. Transgenesis
Transgenesis is a process
whereby an isolated DNA
fragment is introduced into an
animal so that the resulting
animal expresses a desired trait.
This biotechnology is widely
used for improving disease
resistance, enhancing production
traits, and developing
biopharmaceuticals in livestock.
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BENEFITS OF ANIMAL BIOTECHNOLOGY TECHNIQUE
Cost saving and effectiveness.
Convenience and safety.
Tremendous shortening of generation interval.
Maintenance of superior females.
Prevention from extinction and environmental sustainability.
Preservation of desirable trait.
Production of desirable sex.
Increment of the rate of genetic gain.
Generation of high-quality low-cost embryo
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Risk associated with Animal Biotechnology
Ethical concerns
Loss of genetic diversity
Unintended genetic effects and mutations
Environmental impact and ecosystem disruption
Antibiotic resistance development
Food safety and allergenicity risks
Economic inequality and accessibility issues
Regulatory and legal challenges
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Artificial insemination
•Artificial insemination is the technique in which semen with living sperms is
collected from the male and introduced into female reproductive tract at proper
time with the help of instruments.
•In this process, the semen is inseminated into the female by placing a portion of it
either in a collected or diluted form into the cervix or uterus by mechanical
methods at the proper time and under most hygienic conditions.
•The first scientific research in artificial insemination of domestic animals was
performed on dogs in 1780 by the Italian scientist, Lazanno Spalbanzani.
•His experiments proved that the fertilizing power reside in the spermatozoa and
not in the liquid portion of semen.
•In artificial insemination the germplasm of the bulls of superior quality can be
effectively utilized with the least regard for their location in far away places.
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SYMPTOMS OF HEAT
1.The animal will be excited condition.
2.The animal will be in restlessness and nervousness.
3.The animal will be bellowing frequency.
4.The animal will reduce the intake of feed.
5.Peculiar movement of limbo sacral region will be observed.
6.The animals which are in heat will lick other animals and smelling other animals.
7.The animals will try to mount other animals
8.The animals will standstill when another animal try to mount.. This period is known as
standing heat. This extends 14-6 hours.
9.Frequent maturation (urination) will be observed.
10.Clear mucous discharge will be seen from the vulva, sometimes it will be string like the
mucous will be seen stick to the near the pasts of vulva.
11.Swelling of the vulva will be seen.
12.The tail will be in raised position.
13.Milk production will be slightly decreased.
14.On Palpation uterus will be turgid and the cervix will be opened.
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ADVANTAGES OF ARTIFICIAL INSEMINATION
1.There is no need of maintenance of breeding bull for a herd; hence the cost of maintenance of breeding bull
is saved.
2.It prevents the spread of certain diseases and sterility due to genital diseases. Eg: contagious abortion,
vibriosis.
3.By regular examination of semen after collection and frequent checking on fertility make early detection of
interior males and better breeding efficiency is ensured.
4.The progeny testing can be done at an early age.
5.The semen of a desired size can be used even after the death of that sire.
6.The semen collected can be taken to the urban areas or rural areas for insemination.
7.It makes possible the mating of animals with great differences in size without injury to either of the animal.
8.It is helpful to inseminate the animals that are refuse to stands or accept the male at the time of estrus.
9.It helps in maintaining the accurate breeding and cawing records.
10.It increases the rate of conception.
11.It helps in better record keeping.
12.Old, heavy and injured sires can be used.
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DISADVANTAGES OF A.I.
•Requires well-trained operations and special equipment.
•Requires more time than natural services.
•Necessitates the knowledge of the structure and function of reproduction on
the part of operator.
•Improper cleaning of instruments and in sanitary conditions may lead to
lower fertility.
•If the bull is not properly tested, the spreading of genital diseases will be
increased.
•Market for bulls will be reduced, while that for superior bull is increased.
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Semen Collection
•In animals, semen collection is a critical part of breeding management
and artificial insemination (AI) programs, especially in livestock like
cattle, sheep, goats, and horses. Here's a more detailed look at the
process of semen collection in animals:
a.Preparation of animal
b.Method of semen Collection
c.Collection and Handling of Semen
d.Semen Processing and Preservation
e.Storage and Transport
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Collection of Semen from Bull
➢Artificial vagina technique
➢Cylindrical rubber tube
➢Thin rubber liner
➢Thin walled rubber cone
➢Collection vial
➢Insulated Jacket
➢Electroejaculation
➢Per rectal massage of genital organs
❖Collection is generally made every second day.
❖Two ejaculates are collected per day.
❖AV temperature 45
o
C

1. Preparation of the Animal:
•Animal Selection: Males with good genetics, health, and reproductive
performance are selected for semen collection.
•Restraint: The animal is properly restrained to ensure both safety and ease of
semen collection. Depending on the species, this can be done using a halter or
other physical barriers.
•Cleanliness: The genital area of the male is cleaned to prevent contamination of
the semen
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2. Methods of Semen Collection:
a. Artificial Vagina (AV): The artificial vagina is one of the most widely used tools for semen
collection in animals, particularly in cattle, stallions, and rams. It simulates the female
reproductive tract. It consists of a tube filled with warm water to mimic the conditions of the
female’s reproductive tract, which encourages ejaculation. The male is encouraged to mount a
dummy animal or is placed in a position where it can naturally ejaculate into the artificial
vagina.
b. Electro-Ejaculation: If the male animal is not responsive to the AV or cannot be trained to
mount, an electro-ejaculator may be used. This device sends a mild electrical impulse to the
rectum to stimulate the ejaculation reflex. The device is inserted into the rectum, and the
electrical current stimulates the pelvic muscles, causing ejaculation.
c. Manual Stimulation: Manual collection is sometimes employed, especially in species like
goats, where the male may be manually stimulated by a trained technician. The male is usually
restrained, and the technician carefully collects the semen manually.
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3. Collection and Handling of Semen
•The collected semen is transferred to a clean container. In the case of the AV
method, the semen is collected directly into the AV. The semen is carefully
examined for sperm motility, concentration, and morphology (shape and
structure). High-quality semen is essential for successful AI.
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4. Semen Processing
➢Semen processing includes semen testing and semen extension.
a.Testing: The thickness or density of the semen is tested in the semen analyzer,
which estimates the number of sperm. Next the semen is examined under
microscope to evaluate motility and morphology of sperm.
✓80 % motility is excellent
✓70% is good
✓50-60% is fair
➢Abnormal appearances such as coiled tails, tailless, irregular shaped heads and
double heads or tails, may result from cold or heat shock, poor nutrition, and
endocrine imbalances .
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b. Semen extension
➢The male ejaculates millions of sperm at the time of mating.
➢Collected semen can be extended, or diluted, so that one ejaculation may be used
to breed many females.
Objectives of extension of semen
•To increase the volume of the ejaculate.
•To aid in preserving the viability of spermatozoa.
•To inseminate large number of female from a single ejaculate.
Semen extenders
1.Egg yolk citrate extender
2.Whole milk extender
3.Milk-glycerol extender
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5. Semen Preservation
•Semen can be frozen and stored for indefinite periods.
•British scientists discovered that addition of glycerol to semen
extender improved resistance of sperm to freezing in 1949.
•Glycerol removes water from the sperm before freezing.
•Its also prevents the ice crystals from damaging the sperm.
•After dilution semen are kept in straw (preserved in liquid
nitrogen) in -196 °C.
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Thawing
•The process of changing the
frozen semen into the liquid
form for the use 35-37° C.
•Put straw in the thaw water not
more than 3 seconds exposure
to air.
•Straws of semen should be
used within 15 minutes after
thawing.
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INSEMINATION METHOD
RECTO VAGINAL INSEMINATION METHOD
•In cattle the safe and best method of insemination is “Recto vaginal method of
insemination”. Cow which is in heat is well controlled placing it in a Travis. The
inseminator will get ready by wearing a plastic apron, gumboots and gloves. The
semen straw after thawing (keeping the semen straw in warm water for a minute to
convert the freeze semen into liquid and the sperms become motile) is loaded in a
sterilized A.I. gun and is covered with a plastic sheath. The inseminator will insert
the gloved left hand into the rectum after applying the soft soap or other lubricant
on the glove and back racked the animal, and the hand is further inserted and will
catch hold the cervix through rectal wall. The A.I gum loaded with semen straw is
passed.
•Through the vulva to vagina and cervix and observed with the hand in rectum that
the A. I gun reaches the cervix, then the semen is deposited by injecting the gun,
and after depositing the semen the gun is removed, the empty straw and sheath are
disordered.
Boby Basnet/Assistant Professor 248

Time of insemination
Cows showing estrusInseminated Too late for good
results
In morning Same day Next day
In afternoon Morning of next day or
early afternoon
After 3 p.m.
Boby Basnet/Assistant Professor 249

Multiple Ovulation & Embryo Transfer (MOET)
Technology Collection & Transfer of Embryo
Boby Basnet/Assistant Professor 250

Embryo transfer technology
•Embryo transfer is a bio-technique where embryos are collected from the
donor females and transferred into the uterus of recipients which serves as a
foster mother for its development through out the remainder period of
pregnancy.
Boby Basnet/Assistant Professor 251

Steps Involved In Embryo Transfer
1.Selection of donor.
2.Selection of recipient.
3.Estrus synchronization of donor and recipient.
4.Superovulation/Multiple ovulation of donor.
5.Artificial insemination of donor.
6.Embryo collection.
7.Evaluation of embryo.
8.Transfer of embryo/Cryopreservation of embryo/Micromanipulation.
Boby Basnet/Assistant Professor 252

1. Selection Criteria of Donor
1.Superior individual performance.
2.Good productive performance of offspring.
3.Regular cyclicity.
4.Ovaries must be free (No adhesions).
5.Intact tubular genitalia (Free from any sort of abnormalities).
6.Younger (4-8 Yrs. Of age).
7.Healthy and have good body weight.
8.Must have calved at least 60 days back (best 90-100 days post partum).
9.Normal post partum history.
10.A history of no more than two mating per conception
11.Previous calves having been born at approximately 365-day intervals.
12.An appropriate body condition score at the time of embryo transfer
Boby Basnet/Assistant Professor 253

2. Selection Criteria of Recipient
➢Healthy, free from infection and have good body weight.
➢Regular cyclicity.
➢Intact genitalia (free from any sort of abnormalities)
➢Must have good cyclic CL of desired stage at the time of embryo transfer.
➢Exhibit calving ease, and that have good milking and good mother ingability.
3. Estrus Synchronization of Donor
➢Estrus synchronization is a reproductive management technique that involves
manipulating a cow's estrous cycle so that multiple cows are in heat at the same time.
Synchronization of fertile estrus in heifers can be accomplished withprogestogens,
combinations of progestogens and prostaglandin F2α, prostaglandin F2α alone, and
combinations of gonadotrophin-releasing hormone and prostaglandin F2α.
Boby Basnet/Assistant Professor 254

4. Super ovulation/Multiple Ovulation of Donor Cow
➢Is the procedure for increased ovulatory response by administration of hormones
(gonadotropins) to produce several ova instead of one which is normally produced at
each estrus
➢This large number of ova is later on fertilized, and embryo produced can be transferred
to the other females.
➢The basic principle of superovulation is to stimulate extensive follicular development
through the use of a hormone preparation, which is given in Tra muscularly or
subcutaneously, with Follicle Stimulating Hormone (FSH) activity.
➢In the ewe, doe and cow, an average of 12 ovulations can be expected.
➢In sows, the number of ovulation could be >20.
Time of Superovulation
➢For optimum response, gonadotropin treatment is initiated during mid-luteal phase i.e.
on days 9-14.
➢Donor cows can be super ovulated repeatedly at approximately 6-8 weeks intervals.
Boby Basnet/Assistant Professor 255

5. Insemination of Donor (AI)
➢Donor should be inseminated artificially 2-3 times at 12 hours, 24 hours and 36 hours
interval, beginning at 8-10 hours after the onset of estrus.
➢This is required because ovulation can occur over an extended time.
➢Fresh semen is preferred.
➢If frozen semen: Then use double insemination dose at each insemination.
6. Embryo Recovery/Embryo Flusing
➢Embryo can be collected by following methods:
a.Surgical method
b.Non-surgical method
Boby Basnet/Assistant Professor 256

a) Surgical method
➢Surgical method is most often used in sheep, goat and swine through mid-ventral
incision under general anesthesia.
➢The method can be performed on day 3-4 after estrus in sheep and goat (8-cell
embryo or less) & on 2-3 days after estrus in swine (4-cell stage).
Boby Basnet/Assistant Professor 257

b. Non-surgical collection (Transcervical method)
➢Embryo flushing in cattle, buffalo, and mares uses a two or three way Foley’s
catheter, allowing fluid to pass into and return from the uterus, with a small
balloon preventing fluid escape through the cervix.
➢Embryos are collected 6-8 days post-breeding in cattle and buffalo at the
compact morula or blastocyst stage, and 6-7 days post-ovulation in mares at
the blastocyst stage.
➢Modified Dulbecco’s phosphate-buffered saline is the preferred flushing
medium, though normal saline can be used if unavailable.
➢During final collection, 50 IU of oxytocin is administered intravenously, and
large doses of antibiotics help prevent infection.
Boby Basnet/Assistant Professor 258

b. Non-surgical collection (Transcervical method)
Boby Basnet/Assistant Professor 259

Boby Basnet/Assistant Professor 260

7. Evaluation of embryo
➢After collection and before transfer to the recipients, the embryos are evaluated
under stereomicroscope at 50-100 X magnification.
➢Day 7 bovine embryos (compact morula or blastocyst) are about 150-190μ m in
diameter.
➢Embryos are graded based on following characteristics.
➢Compactness of the cells
➢Regularity of shape
➢Variation in cell size
➢Color and texture of cytoplasm
➢Presence of vesicles, extruded cells, cellular debris
Boby Basnet/Assistant Professor 261

Using this criteria, the embryos are graded as:
GradesTypes Characteristics
I. Excellent Symmetrical, compact, distinct outline, no blastomere extrusion, even
granulation, neither very light nor very dark.
II. Good Somewhat asymmetric, even granulated with distinct outline, some
blastomere extrusion.
III. Fair Hazy outline, extruded cell, asymmetric.
IV. Poor Uneven granulation, hazy outline, abnormal shaped.
V. Degenerative Development stage difficult to determine.
Boby Basnet/Assistant Professor 262

8.Transfer of embryo (Introduction to recipient)
➢Recipient should be in estrus within 12 hours of the donor so that it should posses' good CL at the time of transfer.
a)Surgical method:
➢A small syringe is used to make the transfer.
➢When the embryo is placed in the uterus, the needle is carefully inserted through the wall of uterine horn whereas, when
embryo is placed in oviduct then the needle is inserted through the infundibulum into the ampulla where the embryo is
deposited.
b) Non-surgical method
➢Flushed embryos that pass inspection are loaded into an AI straw.
➢If the embryo is frozen it is thawed in a warm water bath (92°F) for <30 sec and placed in a specially designed transfer
gun and covered with a sterile sheath.
➢The transfer gun is passed through the vagina, cervix, and into the uterine horn on the side as the CL. The embryo is
deposited 1/3 the way up the uterine horn.
➢Recipients should be in heat 12 hours after the donor was in estrus.
➢The embryos are typically transferred on day 7 of the estrous cycle.
Boby Basnet/Assistant Professor 263

Storage and Cryopreservation of Embryo
➢Embryos can be maintained at near body temperature in the media used for flushing during the period
between recovery and transfer.
➢If embryos are to be held longer than 2 hrs. up to 10 hrs., a media containing 20% heat treated serum
should be used as a holding medium.
➢If embryos are cooled at -5°C (Refrigerated temperature), they can be maintained for 2-4 days.
➢Cryopreservation of embryo is performed for longer Worldwide.
Advantages of Cryopreservation
➢Long term storage.
➢Eliminates estrus synchronization in recipients.
➢Worldwide distribution.
➢Easy export and import.
➢Cryoprotectants like glycerol, ethylene glycol and DMSO (Dimethyl sulpho oxide) a real ways needed for
preservation of embryos.
Boby Basnet/Assistant Professor 264

Thawing of Straws
➢Straws are thawed before transfer of embryo to the recipients.
➢If 0.25 ml straw-15 sec. in air and 20 sec in water bath at 37ºC.
➢If 0.5 ml straw-20 sec. in air and 20 sec in water bath at 37ºC.
➢Exposure to air reduces damage to the zona pellucida.
Advantages ETT Program:
➢Increase the number of off spring sired from superior females.
➢Results in faster genetic progress.
➢Increase the frequency of desired mating, capitalizing on excellence of a mating.
➢Obtain off spring from old or injured animals in capable of breeding or calving naturally.
➢Increased farm income through embryo sales.
➢Exportation and/or importation of embryos is easier than with live animals.
Disadvantages of EET Program:
➢Can be cost prohibitive and success rates are less than AI.
➢Cost and maintenance of recipient females.
equires a technician with the skills to flush embryos from the reproductive tract.
➢Possible spread of disease through recipients.
265

Pregnancy diagnosis
➢Pregnancy diagnosis by ultrasound imaging at day 42-45 post
transfer
1. Rectal Palpation (Most Common and Traditional Method):
➢Performed around 35 to 45 days after breeding.
➢A trained veterinarian or technician feels the reproductive tract
through the rectum to check for signs like asymmetry of the
uterine horns, presence of fluid, fetal membranes, or the fetus
itself.
Advantages: Quick, inexpensive, and reliable in skilled hands.
Disadvantages: Requires expertise, and rough handling can
harm the cow or pregnancy.
Boby Basnet/Assistant Professor 266

2. Ultrasound Examination
•Can detect pregnancy as early as 26 to 30 days
post-breeding.
•Uses an ultrasound probe inserted rectally to
visualize the fetus, heartbeat, and placental
structures.
•Advantages: Highly accurate, allows assessment
of fetal viability and age.
•Disadvantages: Requires specialized equipment
and training, and it’s more costly
Boby Basnet/Assistant Professor 267

3. Blood or Milk Progesterone Test
•Measures progesterone levels 18 to 24 days after
breeding. High progesterone suggests pregnancy.
•Advantages: Simple and can be done on-farm with
lab support.
•Disadvantages: False positives can occur if the cow is
in diestrus or has reproductive issues
Boby Basnet/Assistant Professor 268

Reproductive system of ruminants and
non-ruminants.
Boby Basnet/Assistant Professor
Boby Basnet/Assistant Professor/Animal Science

Reproduction in Cattle
Male Reproductive System (Bull)
The male reproductive organs produce the male gametes, the
spermatozoans. These are introduced into female reproductive
system, where they fuse with the ovum to form zygote. The
reproductive system(bull) is composed of the following parts:
1.Testes
2.Epididymis
3.Vas deferens
4.Urethra
5.Prostate gland
6.Seminal vesicles
7.Bulbourethral gland (Cowper's gland)
8.Penis
Boby Basnet/Assistant Professor/Animal Science

1.Testes: A bull has two testes, which are responsible for production of sperm and male sex hormone
testosterone. The testes are located in the scrotum, which regulates the temperature of the testes to ensure
optimal sperm production.
2.Epididymis: The epididymis is a coiled tube that is attached to the testes and serves as a site for sperm
maturation and storage. Transport and store sperm cells produced by testes, bring sperm to maturity.
3.Vas deferens: The vas deferens is a muscular tube that transports sperm from the epididymis to the urethra.
4.Urethra: The urethra is a tube that runs through the penis and carries semen and urine out of the body. During
ejaculation, semen is deposited in the female reproductive tract.
5.Prostate gland: The prostate gland is a gland that secretes a fluid that forms part of the semen. The fluid
provides nourishment for the sperm and helps to protect them from the acidic environment of the female
reproductive tract.
6.Seminal vesicles: The seminal vesicles are a pair of glands that secrete a fluid that also forms part of the
semen. The fluid contains fructose, which provides energy for the sperm.
7.Bulbourethral glands (Cowper’s Gland): The bulbourethral glands are a pair of small glands that secrete a
fluid that lubricates the urethra and neutralizes any remaining urine in the urethra prior to ejaculation.
8.Urethra: Passage to carry sperm and urine.
9.Penis: It is a copulatory organ, also used for urination.
Boby Basnet/Assistant Professor/Animal Science

The Female Reproductive System (Cow)
The Female Reproductive System (Cow)
1.Ovaries
2.Fallopian tubes
3.Uterus
4.Vagina
5.Vulva
Boby Basnet/Assistant Professor/Animal Science

1.Ovaries
•The two ovaries are in the abdomen, on the left and right sides.
•They produce ova (eggs) and hormones that control the sexual cycle.
•The hormone estrogen is produced by the Graafian follicle inside the ovary under the influence of
another hormone called the Follicle Stimulating Hormone (FSH).
•Estrogen induces estrus, commonly known as the heat period, during which the cow shows signs of
being in heat.
•Approximately every 21 days, the ovary releases a mature ovum, and the cow comes into heat.
•This process of releasing the ovum and its movement down to the uterus through the fallopian tubes is
called ovulation.
•If mating occurs during this period, fertilization can take place.
•The fertilized egg then implants itself onto the endometrium (the walls of the uterus) and develops into a
fetus.
Boby Basnet/Assistant Professor/Animal Science

2. Fallopian tubes:
➢Fertilization takes place here.
➢Also, a passage for the egg from the ovary to the uterus.
3. Uterus:
➢Implantation takes place here and embryo develops here.
4. Cervix
➢Closes the uterus.
5. Vagina and Vulva:
➢Vulva is the external opening of female reproductive system.
➢It allows mating to take place so that sperms are deposited into the vagina.
➢The fetus and urine are removed through the vulva.
Boby Basnet/Assistant Professor/Animal Science

Reproduction in Poultry
The reproductive system has the following parts:
1.Ovary
2.Funnel (Infundibulum)
3.Magnum
4.Isthmus
5.Uterus/Shell gland
6.Vagina
7.Cloaca
Boby Basnet/Assistant Professor/Animal Science

1.Ovary: Hen has two ovaries but one functional. Ova is formed in
ovaries. About 3500-4000 ova present inside ovary held by follicle.
Mature ovum released via rapture of follicle. It moves into oviduct
received by the funnel.
2.Funnel (infundibulum): Fertilization occurs here. Chalaza also added
to yolk. It also collects the ovum and stores the sperm. Time here is 15
minutes, and it is 11.6cm long.
3.Magnum: Thick albumen is added and stays for 3 hrs. its 33 cm long.
4.Isthmus: Its 10.6cm long, Shell membranes added and determines
shape of egg. Water, mineral salts and vitamins added and takes 15
minutes.
5.Uterus (shell gland): Calcium deposits i.e. shell added around the
egg. Pigments added. Addition of albumin finished and stays here for
18-22hours.
6.Vagina: Short, 6.9 cm long and for temporal storage of egg before
laying
7.Cloaca: Egg moves out of cloaca through the vent and the cloaca
extents out to prevent the egg from breaking.
Boby Basnet/Assistant Professor/Animal Science

Reproductive Tract of pig (Female)
1.Ovaries
2.Infundibulum
3.Oviduct
4.Uterine horn
5.Uterine body
6.Cervix
7.Vagina
8.Vulva
Boby Basnet/Assistant Professor/Animal Science

1. Ovaries
➢To produce ova, the female germ cells and hormones progesterone and estrogen.
2. Infundibulum
➢Acts like a funnel to collect ova and diverts ova to the oviducts.
3. Oviducts
➢6 to 10 inches long and acts as site of fertilization.
4. Uterine Horns
➢ 2-3 feet in a non-pregnant sow, act as a passageway for sperm and are the site of fetal development.
5. Cervix
➢Muscular junction between the vagina and uterus, Site of semen deposit.
6. Vagina.
➢Extends from the cervix to the vulva
➢Passageway for urine and piglets
7. Vulva
➢External part of the reproductive tract
➢Becomes red and swollen just prior to estrus
Boby Basnet/Assistant Professor/Animal Science

Good luck for your exam
Boby Basnet/Assistant Professor/Animal Science

Principle and Practices of Animal Breeding || Boby Basnet

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Principle and Practices of Animal Breeding || Boby Basnet

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