4 Reproductive Physi vcxvfdology- DY.pdf
SantoshBhandari52
35 views
113 slides
Sep 22, 2024
Slide 1 of 113
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
About This Presentation
dsge
Slide Content
Reproductive Physiology
By: Dagmawi Yitbarek (DVM, MSc)
1
By: Dagmawi Yitbarek (DVM, MSc)
1
Reproduction
•Reproduction is the formation of new individuals, which
may occur by asexual or sexual methods.
•In the asexual methods, which occur mainly among the
lower animals, the offspring are derived from a single
individual and they are genetically identical to the
parent.
•In sexual methods, offspring ordinarily derived from the
paired union of special cells, the gametes, from two
individuals.
•Basic to all processes of reproduction is the origin of the new
individual from one or more living cells of the parent or
parents.
2
•Reproduction is the formation of new individuals, which
may occur by asexual or sexual methods.
•In the asexual methods, which occur mainly among the
lower animals, the offspring are derived from a single
individual and they are genetically identical to the
parent.
•In sexual methods, offspring ordinarily derived from the
paired union of special cells, the gametes, from two
individuals.
•Basic to all processes of reproduction is the origin of the new
individual from one or more living cells of the parent or
parents.
2
Importance of reproduction
The importance of reproduction
1.To create next generation
•Unique property of a particular organism is transferred from
one generation to the next generation through genes, which
are situated in the DNA.
•During meiosis number of chromosomes become half of
that in the parent cells.
•As a result when both male and female gametes fuse to
form zygote, the number of chromosomes becomes
adequate for the species involved.
•Thus, reproduction ensures that animal species does not
disappear from Earth=> maintain the continuity of the
species
3
The importance of reproduction
1.To create next generation
•Unique property of a particular organism is transferred from
one generation to the next generation through genes, which
are situated in the DNA.
•During meiosis number of chromosomes become half of
that in the parent cells.
•As a result when both male and female gametes fuse to
form zygote, the number of chromosomes becomes
adequate for the species involved.
•Thus, reproduction ensures that animal species does not
disappear from Earth=> maintain the continuity of the
species
3
Cont…
2. To create variations in species
–As no two individuals are same, so genetic characters
from both parents will help make a slightly different copy of
themselves.
–These small variations accumulate over hundreds of years
resulting in formation of new species.
4
2. To create variations in species
–As no two individuals are same, so genetic characters
from both parents will help make a slightly different copy of
themselves.
–These small variations accumulate over hundreds of years
resulting in formation of new species.
4
Events of Reproduction
•Puberty- Age at which reproductive organs become
functional
–male & female gonads are capable of releasing
gametes
•Female- Reproduction process occurs within
–Estrous cycle- Repetitive cycle occurring when
pregnancy does not
–Estrus- “Heat” or receptivity to mating
•Fertilization- Egg & Sperm unite
–Only real male contribution is the sperm
•Gestation- Length of time of pregnancy
•Parturition- Act of giving birth
•Puberty- Age at which reproductive organs become
functional
–male & female gonads are capable of releasing
gametes
•Female- Reproduction process occurs within
–Estrous cycle- Repetitive cycle occurring when
pregnancy does not
–Estrus- “Heat” or receptivity to mating
•Fertilization- Egg & Sperm unite
–Only real male contribution is the sperm
•Gestation- Length of time of pregnancy
•Parturition- Act of giving birth
Age at puberty in females
Cows 7 to 18 months
Ewes 7 to 10 months
Does 4 to 5 months
Mare 12 to 24 months
Swine 4 to 8 months
Bitch 6-20 months
Queen 7-12 months
Cows 7 to 18 months
Ewes 7 to 10 months
Does 4 to 5 months
Mare 12 to 24 months
Swine 4 to 8 months
Bitch 6-20 months
Queen 7-12 months
Age at puberty in males
A number of factors influence the age at which an animal
reaches puberty.
8
Factors influencing the age at puberty
reaches puberty.
8
Factors influencing the age at puberty
Animal species
–Smaller species usually reach puberty before larger species
Breed
•Some breeds within a species reach puberty earlier than
other breeds.
•Dairy breed appear to reach puberty earlier than beef breeds.
•Breeds of a larger size at maturity are older & heavier when
reaching puberty.
•The larger breeds of cattle & horses have a late onset of
puberty than the smaller breeds.
–In cattle, Hereford and Angus reach puberty before Brahma
and Zebu.
Sex
₋The female of the species usually reaches puberty earlier
than male animal.
–Smaller species usually reach puberty before larger species
Breed
•Some breeds within a species reach puberty earlier than
other breeds.
•Dairy breed appear to reach puberty earlier than beef breeds.
•Breeds of a larger size at maturity are older & heavier when
reaching puberty.
•The larger breeds of cattle & horses have a late onset of
puberty than the smaller breeds.
–In cattle, Hereford and Angus reach puberty before Brahma
and Zebu.
Sex
₋The female of the species usually reaches puberty earlier
than male animal.
Body weight
₋Body weight plays more important role than the age for
attaining puberty and sexual maturity.
₋The effect of weight at puberty onset differs among various
breeds of cattle and other species.
₋It is generally considered that heifers attain puberty when they
attain 55 to 60 % of adult weight.
Management system
₋The type of housing, lighting, and pen arrangement have
great impact on onset puberty
Stress
₋recent studies indicate that low levels of stress results in
early onset of puberty.
₋excess stress, however, may delay the onset of puberty.
10
₋Body weight plays more important role than the age for
attaining puberty and sexual maturity.
₋The effect of weight at puberty onset differs among various
breeds of cattle and other species.
₋It is generally considered that heifers attain puberty when they
attain 55 to 60 % of adult weight.
Management system
₋The type of housing, lighting, and pen arrangement have
great impact on onset puberty
Stress
₋recent studies indicate that low levels of stress results in
early onset of puberty.
₋excess stress, however, may delay the onset of puberty.
10
Nutrition
•Adequate, well-balanced diet (protein and energy feed) is
necessary for animals to reach puberty at an optimal time.
•Nutrition affects synthesis and release of GnRH, FSH, LH
and GH due to its action on hypothalamus and anterior
pituitary respectively.
•Leptins are molecules produced by the adipose tissue that
signal the nutritional status of the animal to the central
reproductive axis and heifers with higher plasma leptins
attain puberty earlier.
•Severely malnourished animals will have a delayed onset of
puberty.
•Malnourished females lack ovarian activity owing to the
suppression of luteinizing hormone in a pulsatile fashion.
11
•Adequate, well-balanced diet (protein and energy feed) is
necessary for animals to reach puberty at an optimal time.
•Nutrition affects synthesis and release of GnRH, FSH, LH
and GH due to its action on hypothalamus and anterior
pituitary respectively.
•Leptins are molecules produced by the adipose tissue that
signal the nutritional status of the animal to the central
reproductive axis and heifers with higher plasma leptins
attain puberty earlier.
•Severely malnourished animals will have a delayed onset of
puberty.
•Malnourished females lack ovarian activity owing to the
suppression of luteinizing hormone in a pulsatile fashion.
11
Climate
₋Animal generally have an earlier onset of puberty in warmer
climates,
₋However excessive heat (high environmental temperature)
may actually delay the onset of puberty.
Season
₋Many breeds and species of animals are seasonal breeders.
Long-day breeders breed during increasing day length.
₋Mare, queen and swine are examples of long-day
breeders.
Short-day breeders begin to cycle and are most fertile
during decreasing day length.
₋Sheep and goats are examples of species that are
normally fertile and actively breeding during decreasing
day length.
12
₋Animal generally have an earlier onset of puberty in warmer
climates,
₋However excessive heat (high environmental temperature)
may actually delay the onset of puberty.
Season
₋Many breeds and species of animals are seasonal breeders.
Long-day breeders breed during increasing day length.
₋Mare, queen and swine are examples of long-day
breeders.
Short-day breeders begin to cycle and are most fertile
during decreasing day length.
₋Sheep and goats are examples of species that are
normally fertile and actively breeding during decreasing
day length.
12
Other factors
Age at puberty in sheep & goat is affected by month of birth.
Poor health & poor sanitation in rearing facilities delays
puberty.
Feeding above recommended levels will result in early
puberty.
The presence mature animals will affect the onset of puberty.
Heifers that are exposed for bull have earlier onset of
puberty than not exposed heifers…..pyschological.
Age at puberty in sheep & goat is affected by month of birth.
Poor health & poor sanitation in rearing facilities delays
puberty.
Feeding above recommended levels will result in early
puberty.
The presence mature animals will affect the onset of puberty.
Heifers that are exposed for bull have earlier onset of
puberty than not exposed heifers…..pyschological.
Sexual maturity
Sexual maturity is the age at which the animal attains full
reproductive capacity after puberty.
The animal reaches its maximum reproductive potential.
The female become capable for insemination & pregnancy.
Appearance of enough sperm in ejaculate to impregnate
females.
Sexual maturity is the age at which the animal attains full
reproductive capacity after puberty.
The animal reaches its maximum reproductive potential.
The female become capable for insemination & pregnancy.
Appearance of enough sperm in ejaculate to impregnate
females.
Terms
Gamete: egg or sperm
Gametogenesis: formation & development of gametes
Oogenesis: production of eggs
Spermatogenesis: production of sperms
Spermiogenesis: differentiation of sperm morphology
Follicle: where eggs mature in the ovary
Ovulation: release of egg from follicle
Polar body: nonfunctional product of meiotic divisions in oogenesis
Zygote: Fertilized egg
Gamete: egg or sperm
Gametogenesis: formation & development of gametes
Oogenesis: production of eggs
Spermatogenesis: production of sperms
Spermiogenesis: differentiation of sperm morphology
Follicle: where eggs mature in the ovary
Ovulation: release of egg from follicle
Polar body: nonfunctional product of meiotic divisions in oogenesis
Zygote: Fertilized egg
Male reproductive system
Testes (primary organ)
Vas deferens, epididymis and urethra (internal duct system)
External genitalia (penis and scrotum)
Accessory sex glands
seminal vesicle, prostate gland, &
bulbourethral gland)
Muscles
blood supply
nerves
Testes (primary organ)
Vas deferens, epididymis and urethra (internal duct system)
External genitalia (penis and scrotum)
Accessory sex glands
seminal vesicle, prostate gland, &
bulbourethral gland)
Muscles
blood supply
nerves
Testicles-
–Site of sperm
production and
testosterone synthesis
–Sperm contain ½ of
genetic makeup
Epididymis-
–Sperm storage and
maturation
Scrotum-
–Protects testes and
regulates temperature
http://biotech-adventure.okstate.edu/low/basics/reprod/animal/male/diagram/
Cont…
–Site of sperm
production and
testosterone synthesis
–Sperm contain ½ of
genetic makeup
Epididymis-
–Sperm storage and
maturation
Scrotum-
–Protects testes and
regulates temperature
http://biotech-adventure.okstate.edu/low/basics/reprod/animal/male/diagram/
Cont…
Vas Deferans-
–Transports sperm
from epididymis to
urethra
Urethra-
–tube inside of penis
transports sperm or
urine exterior
Penis-
–organ of copulation
http://biotech-adventure.okstate.edu/low/basics/reprod/animal/male/diagram/
Cont…
–Transports sperm
from epididymis to
urethra
Urethra-
–tube inside of penis
transports sperm or
urine exterior
Penis-
–organ of copulation
http://biotech-adventure.okstate.edu/low/basics/reprod/animal/male/diagram/
Cont…
Accessory sex glands (bull)
General functions of male reproductive system
-produce, maintain, and transport mature
spermatozoa (the male gametes),
-produce nutritive and protective fluid (semen), and
- discharge the spermatozoa-containing semen within
the female reproductive tract during mating.
Produce, maintain, and transport mature spermatozoa.
Produce and transport semen (nutritive & protective
fluid).
Discharge and deposit the spermatozoa-containing
semen within the female reproductive tract during
mating.
Secretion of hormones.
-produce, maintain, and transport mature
spermatozoa (the male gametes),
-produce nutritive and protective fluid (semen), and
- discharge the spermatozoa-containing semen within
the female reproductive tract during mating.
Produce, maintain, and transport mature spermatozoa.
Produce and transport semen (nutritive & protective
fluid).
Discharge and deposit the spermatozoa-containing
semen within the female reproductive tract during
mating.
Secretion of hormones.
Testes and associated structures
Testes are responsible for the formation of sperm.
The mammalian testes are divided into many lobules, and
each lobule contains many tiny seminiferous tubules
where sperm are produced (spermatogenesis).
The seminiferous tubules are convoluted and occupy the
greatest portion of each testicle and the other part is interstitial
tissue which is located outside the seminiferous.
Cell types are found within/wall seminiferous tubules.
»Germ cells (spermatogenic cells) found between
sertoli cells
»Sertoli cells
»Leydig's cells
Testes are responsible for the formation of sperm.
The mammalian testes are divided into many lobules, and
each lobule contains many tiny seminiferous tubules
where sperm are produced (spermatogenesis).
The seminiferous tubules are convoluted and occupy the
greatest portion of each testicle and the other part is interstitial
tissue which is located outside the seminiferous.
Cell types are found within/wall seminiferous tubules.
»Germ cells (spermatogenic cells) found between
sertoli cells
»Sertoli cells
»Leydig's cells
22
Sertoli cells
Supporting cells or "nurse" cell of the testicles.
Nourish & support the developing sperm cell.
They form blood-testis barrier to control
spermatogenesis.
Release spermatids as sperm.
Phagocytosed degenerating germ cells & residual
bodies.
Inhibit spermatogenesis before puberty and stimulate the
process after puberty.
Secret inhibin which negatively regulates FSH
secretion.
Secret aqueous fluid in the lumen of seminiferous tubule
which helps the transport of sperm throughout
epididymis tubule.
Sertoli cells
Supporting cells or "nurse" cell of the testicles.
Nourish & support the developing sperm cell.
They form blood-testis barrier to control
spermatogenesis.
Release spermatids as sperm.
Phagocytosed degenerating germ cells & residual
bodies.
Inhibit spermatogenesis before puberty and stimulate the
process after puberty.
Secret inhibin which negatively regulates FSH
secretion.
Secret aqueous fluid in the lumen of seminiferous tubule
which helps the transport of sperm throughout
epididymis tubule.
Leydig cells/interstitial cells or steroidogenic cell
₋Located between seminiferous tubules or adjacent to it.
₋Lie outside the seminiferous tubules.
₋They are endocrine cells.
₋Responsible for androgen production in response to LH.
₋Responsible for synthesizing & secreting testosterone
(promote dev’t of male reproductive tissues, spermatogenesis
& dev’t of secondary sexual features)
₋Located between seminiferous tubules or adjacent to it.
₋Lie outside the seminiferous tubules.
₋They are endocrine cells.
₋Responsible for androgen production in response to LH.
₋Responsible for synthesizing & secreting testosterone
(promote dev’t of male reproductive tissues, spermatogenesis
& dev’t of secondary sexual features)
Epididymal transport
•The newly formed spermatozoa are essentially immotile.
•They are transported to the epididymis by fluid secretions
into the seminiferous tubules and rete testis.
•The fertilizing ability of an animal is attained progressively
during the transit of spermatozoa through the epididymis.
•During their transit in the epididymis, sperm undergo
maturation processes necessary for them to acquire these
functions.
•Final maturation is completed in the female reproductive tract
(capacitation).
•The newly formed spermatozoa are essentially immotile.
•They are transported to the epididymis by fluid secretions
into the seminiferous tubules and rete testis.
•The fertilizing ability of an animal is attained progressively
during the transit of spermatozoa through the epididymis.
•During their transit in the epididymis, sperm undergo
maturation processes necessary for them to acquire these
functions.
•Final maturation is completed in the female reproductive tract
(capacitation).
Sperm Morphology
•An actively motile, free swimming
cell.
•Its morphology consists of adapted
for reaching and fertilizing the egg.
•Consists of a head, neck and a tail
(flagellum).
•Head contains DNA (genetic material)
and acrosomal cap with hydrolytic
enzymes for penetrating the egg.
•Midpiece contains mitochondria to
form ATP for energy.
•Tail (flagellum) used for generating
propulsive forces locomotion.
•An actively motile, free swimming
cell.
•Its morphology consists of adapted
for reaching and fertilizing the egg.
•Consists of a head, neck and a tail
(flagellum).
•Head contains DNA (genetic material)
and acrosomal cap with hydrolytic
enzymes for penetrating the egg.
•Midpiece contains mitochondria to
form ATP for energy.
•Tail (flagellum) used for generating
propulsive forces locomotion.
Regulation of Spermatogenesis
•Spermatogenesis is dependent on gonadotropin stimulation
and testosterone production.
•FSH stimulates proliferation & secretory activity of the sertoli
cells that secretes androgen binding protein (ABP), serves
to transport androgen into the lumen of the seminiferous
tubules.
•LH stimulates interstitial cells to the produce testosterone.
•Testosterone stimulates spermatogenesis with
»supporting the completion of meiosis
»adhesion of elongated spermatids to sertoli cells
»the release of sperm
»form and maintaining blood testis barrier
•Spermatogenesis is dependent on gonadotropin stimulation
and testosterone production.
•FSH stimulates proliferation & secretory activity of the sertoli
cells that secretes androgen binding protein (ABP), serves
to transport androgen into the lumen of the seminiferous
tubules.
•LH stimulates interstitial cells to the produce testosterone.
•Testosterone stimulates spermatogenesis with
»supporting the completion of meiosis
»adhesion of elongated spermatids to sertoli cells
»the release of sperm
»form and maintaining blood testis barrier
Steroidogenesis
•Steroidogenesis is the multistep process for biosynthesis of
steroid hormones from cholesterol including transformation of
one form of steriod to other steroids using enzymes in
mitochondria and SER.
• >90% of steroidogenesis occurs in the gonads by leyding
cells (males) or follicular cells (females).
₋The rest is on adrenal gland cortex and adipose cell.
•The first enzymatic step in steroid synthesize is conversion of
cholesterol in to pregnenolone (immediate precursor ).
• Within the inner mitochondria membrane of adrenocortical
cells, leyding cells, and follicular cells; cholesterol is converted
to pregnenolone by an enzyme called CYP11A1 also called
desmolase.
•Steroidogenesis is the multistep process for biosynthesis of
steroid hormones from cholesterol including transformation of
one form of steriod to other steroids using enzymes in
mitochondria and SER.
• >90% of steroidogenesis occurs in the gonads by leyding
cells (males) or follicular cells (females).
₋The rest is on adrenal gland cortex and adipose cell.
•The first enzymatic step in steroid synthesize is conversion of
cholesterol in to pregnenolone (immediate precursor ).
• Within the inner mitochondria membrane of adrenocortical
cells, leyding cells, and follicular cells; cholesterol is converted
to pregnenolone by an enzyme called CYP11A1 also called
desmolase.
Products of steroidogenesis (steroids) that shared a typical
(but not identical) ring structure that differs in side chain
attached on it.
(but not identical) ring structure that differs in side chain
attached on it.
Production of steroids in the testis
•The main sex steroid produced in the male is testosterone.
•Testosterone synthesis is induced by luteinizing hormone
and cAMP signaling that promote the transfer of cholesterol
to the inner mitochondrial membrane.
•After that, cholesterol is transformed into progesterone and
subsequently metabolized to testosterone.
•Testosterone influence the differentiation and development
of male genital organs.
•Testosterone can then be converted (mostly in peripheral
tissue) in to Dihydrotestosterone (DHT) by 5α-reductase, or
to estrogen
by cytochrome P450 aromatase.
•The main sex steroid produced in the male is testosterone.
•Testosterone synthesis is induced by luteinizing hormone
and cAMP signaling that promote the transfer of cholesterol
to the inner mitochondrial membrane.
•After that, cholesterol is transformed into progesterone and
subsequently metabolized to testosterone.
•Testosterone influence the differentiation and development
of male genital organs.
•Testosterone can then be converted (mostly in peripheral
tissue) in to Dihydrotestosterone (DHT) by 5α-reductase, or
to estrogen
by cytochrome P450 aromatase.
Accessory sex gland secretion/semen
•The prostate gland produces a secretion that buffers the
vaginal pH (neutralize acidic pH).
•The seminal vesicles add fructose to nourish the sperm
and prostaglandins to promote contractions in Female
reproductive tract for the sperm to propelled up the tract.
•The bulbourethral gland (cowpers gland) produces
alkaline mucus like fluid that lubricates the penis and
washes acidic environment of penis.
•These glands secret is thick fluid (semen) containing sperm
and other secretions from the male reproductive system.
•These fluids give nutrition and protection to the sperm to
help them reach the egg for fertilization.
31
•The prostate gland produces a secretion that buffers the
vaginal pH (neutralize acidic pH).
•The seminal vesicles add fructose to nourish the sperm
and prostaglandins to promote contractions in Female
reproductive tract for the sperm to propelled up the tract.
•The bulbourethral gland (cowpers gland) produces
alkaline mucus like fluid that lubricates the penis and
washes acidic environment of penis.
•These glands secret is thick fluid (semen) containing sperm
and other secretions from the male reproductive system.
•These fluids give nutrition and protection to the sperm to
help them reach the egg for fertilization.
31
The Sperm Pathway
Vas deferens
Ejaculated out of Body
Testes (ST)
Rete testis
Epididymis
Seminal vesicles
Ejaculatory duct
Prostate gland
Urethra
During ejaculation
Vas deferens
Ejaculated out of Body
Testes (ST)
Rete testis
Epididymis
Seminal vesicles
Ejaculatory duct
Prostate gland
Urethra
During ejaculation
Copulation and ejaculation
Sequential events of male copulation are
Sexual arousal
Courtship (sexual display)
Erection
Mounting
Intromission
Ejaculation
Dismounting
Sequential events of male copulation are
Sexual arousal
Courtship (sexual display)
Erection
Mounting
Intromission
Ejaculation
Dismounting
Erection
•Penile erection is enlargement, hardening, and firmness of
the penis following the filling of blood vessels of penis
with blood as the first response to sexual arousal.
•Erection is a result of haemodynamic event associated with
–activation of CNS sites involved in regulation of erections
–relaxation of cavernosal smooth muscle and spaces
–raised arterial pressure
–increased blood flow into cavernosal sinuses
–restricted venous return i.e venous occlusion resulting in
penile engorgement and rigidity.
•As cavernosal smooth muscle relaxes and the blood flow to
the penis increases, the increased pooling of blood in the
cavernosal spaces results in penile engorgement.
•Penile erection is enlargement, hardening, and firmness of
the penis following the filling of blood vessels of penis
with blood as the first response to sexual arousal.
•Erection is a result of haemodynamic event associated with
–activation of CNS sites involved in regulation of erections
–relaxation of cavernosal smooth muscle and spaces
–raised arterial pressure
–increased blood flow into cavernosal sinuses
–restricted venous return i.e venous occlusion resulting in
penile engorgement and rigidity.
•As cavernosal smooth muscle relaxes and the blood flow to
the penis increases, the increased pooling of blood in the
cavernosal spaces results in penile engorgement.
•Sexual stimuli for erection could be
₋touch and mechanical stimulation of the penis
₋smell and sound
₋erotic views
• The penis must be erect in order for ejaculation to occur.
•Erection is reversed (flaccid state of penis) when muscles in
the penis contract, stopping the inflow of blood and opening
outflow channels.
₋touch and mechanical stimulation of the penis
₋smell and sound
₋erotic views
• The penis must be erect in order for ejaculation to occur.
•Erection is reversed (flaccid state of penis) when muscles in
the penis contract, stopping the inflow of blood and opening
outflow channels.
view
(occipital)
smell
(rhiencephalon)
imagination
(limbic systems)
touch
(thalamus)
Erection
(occipital)
smell
(rhiencephalon)
imagination
(limbic systems)
touch
(thalamus)
Erection
Erection abnormalities
•Paraphimosis, the inability to completely reduce the penis
into the preputial cavity.
•Phimosis is a condition that causes an animal to be
unable to protrude its penis from its outer orifice.
•Paraphimosis, the inability to completely reduce the penis
into the preputial cavity.
•Phimosis is a condition that causes an animal to be
unable to protrude its penis from its outer orifice.
Mounting and intromission
•Mounting is the stance assumed by the male by which the
penis is brought into apposition with the vulva of the female.
•Successful mounting must be preceded by a receptive
stance on the part of the female.
•Failures in mounting are encountered when there are
»injuries,
»weakness, or
»soreness in the hind limbs of the male.
•Intromission is introduction of the penis into the vagina and
its maintenance within the vagina during coitus.
•Mounting is the stance assumed by the male by which the
penis is brought into apposition with the vulva of the female.
•Successful mounting must be preceded by a receptive
stance on the part of the female.
•Failures in mounting are encountered when there are
»injuries,
»weakness, or
»soreness in the hind limbs of the male.
•Intromission is introduction of the penis into the vagina and
its maintenance within the vagina during coitus.
Ejaculation
•Ejaculation is a reflex action in which semen is forcefully
discharged out the penis and controlled by CNS.
•Triggered when the sexual act reaches a critical level of
excitement and achieved when sperm are released from the
penis.
•Ejaculation is the final stage of coitus in mammalian male
and is mandatory for natural procreation.
•One bull ejaculate (4-6 ml semen) that contains 300 million
up to billion of sperm.
•Only one spermatozoa can fertilize an ovum, & the reminder
of the cells live only for hours with maximum 5 days.
•Ejaculation is a reflex action in which semen is forcefully
discharged out the penis and controlled by CNS.
•Triggered when the sexual act reaches a critical level of
excitement and achieved when sperm are released from the
penis.
•Ejaculation is the final stage of coitus in mammalian male
and is mandatory for natural procreation.
•One bull ejaculate (4-6 ml semen) that contains 300 million
up to billion of sperm.
•Only one spermatozoa can fertilize an ovum, & the reminder
of the cells live only for hours with maximum 5 days.
•Ejaculation is constituted by two distinct phases, emission
and expulsion.
•Ejaculation = emission + propulsion (expulsion)
•Emission
» the first phase of ejaculation with the deposition of seminal
fluid into the urethra bulb
» Contraction of epididymis, vas deferens, seminal vesi +prost.
» Sphincter muscle at the base of bladder contract, preventing
urine from leaking into urethra from bladder.
•Expulsion
₋expulsion semen from dorsal urethra
₋mediated by somatic motor impulses
₋rhythmic contraction bulbospongiousus& ischiocavernosus muscl.
₋Sphincter at base penis relaxes, admitting semen into the penis
₋corpora cavernosa and corpus spongiosum contraction.
•Finally, increased venous outflow, leads to restoring of flaccid
state => detumescence.
and expulsion.
•Ejaculation = emission + propulsion (expulsion)
•Emission
» the first phase of ejaculation with the deposition of seminal
fluid into the urethra bulb
» Contraction of epididymis, vas deferens, seminal vesi +prost.
» Sphincter muscle at the base of bladder contract, preventing
urine from leaking into urethra from bladder.
•Expulsion
₋expulsion semen from dorsal urethra
₋mediated by somatic motor impulses
₋rhythmic contraction bulbospongiousus& ischiocavernosus muscl.
₋Sphincter at base penis relaxes, admitting semen into the penis
₋corpora cavernosa and corpus spongiosum contraction.
•Finally, increased venous outflow, leads to restoring of flaccid
state => detumescence.
Stages of male sexual act
1)Penile erection
•Release of nitric oxide (released from both autonomic nerves
and endothelium) causes relaxation of corporal cavernosal
smooth muscle tissue resulting of increased blood.
•The spongy erectile tissues blood spaces becomes engorged
with blood produce erection when blood flow in the veins is
inhibited.
•Stimulation is provided by the parasympathetic NS.
2. Lubrication
•Mucus is secreted which flows trough the urethra during
intercourse to aid lubrication.
1)Penile erection
•Release of nitric oxide (released from both autonomic nerves
and endothelium) causes relaxation of corporal cavernosal
smooth muscle tissue resulting of increased blood.
•The spongy erectile tissues blood spaces becomes engorged
with blood produce erection when blood flow in the veins is
inhibited.
•Stimulation is provided by the parasympathetic NS.
2. Lubrication
•Mucus is secreted which flows trough the urethra during
intercourse to aid lubrication.
3. Emission (fluid expulsion) & ejaculation (sperm expulsion)
•When the sexual stimulus becomes extremely intense, the
reflex center of the spinal cord begin to emit sympathetic to
initiate emission.
•It begins with the contraction of vas deferens.
–Emission+ ejaculation=orgasm
•An orgasm occurs as rhythmic muscular contractions
compress the urethra and expel the semen => ejaculation.
•After 1-2 minute the erection ceases, and these processes is
called resolution.
42
•When the sexual stimulus becomes extremely intense, the
reflex center of the spinal cord begin to emit sympathetic to
initiate emission.
•It begins with the contraction of vas deferens.
–Emission+ ejaculation=orgasm
•An orgasm occurs as rhythmic muscular contractions
compress the urethra and expel the semen => ejaculation.
•After 1-2 minute the erection ceases, and these processes is
called resolution.
42
Fate of unejaculated sperm
Half of produced sperm not available for ejaculation.
₋ Reabsorbed by excurrent duct system (terminal
segment of the convoluted seminiferous tubules,
straight tubules, and rete testis)
Some selective removal of abnormal sperm in epididymis
Sperm lost in urine
Half of produced sperm not available for ejaculation.
₋ Reabsorbed by excurrent duct system (terminal
segment of the convoluted seminiferous tubules,
straight tubules, and rete testis)
Some selective removal of abnormal sperm in epididymis
Sperm lost in urine
•ABP and testosterone stimulate
spermatogenesis
•Control is negative feed back by
testosterone and inhibin
Hypothalamus
GnRH
Anterior Pituitary
Follicle Stimulating
Hormone
Luteinizing Hormone
Sertoli Cells
Interstitial Cells
Testosterone
Androgen Binding
Protein
Spermatogenesis
Hormonal control of male reproductive physiology
spermatogenesis
•Control is negative feed back by
testosterone and inhibin
Hypothalamus
GnRH
Anterior Pituitary
Follicle Stimulating
Hormone
Luteinizing Hormone
Sertoli Cells
Interstitial Cells
Testosterone
Androgen Binding
Protein
Spermatogenesis
Hormonal control of male reproductive physiology
Temperature control of spermatogenesis
•Why spermatogenesis takes place at a
temperature of 4 or 5
o
C below body
temperature?
•What would happen if the spermatogenesis takes
place at body temperature and How??
•Why spermatogenesis takes place at a
temperature of 4 or 5
o
C below body
temperature?
•What would happen if the spermatogenesis takes
place at body temperature and How??
Why is temperature important for spermatogenesis?
Each 1°C increase in testicular temperature leads to a 14%
decrease in spermatogenesis (15). High ambient
temperature drastically reduces sperm motility through
decreased mitochondrial activity and ATP synthesis (16).
Testicular tissue heated stress leads to apoptosis via
mitochondrial pathways or DNA damage (17)
What could happen to the temperature of the testes and the
sperm production?
Continuous exposure to higher temperatures can cause
sperm production to be lower, or cause the production of
abnormally shaped sperm cells resulting in infertility
Each 1°C increase in testicular temperature leads to a 14%
decrease in spermatogenesis (15). High ambient
temperature drastically reduces sperm motility through
decreased mitochondrial activity and ATP synthesis (16).
Testicular tissue heated stress leads to apoptosis via
mitochondrial pathways or DNA damage (17)
What could happen to the temperature of the testes and the
sperm production?
Continuous exposure to higher temperatures can cause
sperm production to be lower, or cause the production of
abnormally shaped sperm cells resulting in infertility
Physiology of female reproductive tract
•Female reproductive tracts of various farm animals are similar,
but differ primarily in the shape of the uterus and cervix.
•Female reproductive tract consists of
–two ovaries
–two oviducts
–two uterine horns
–uterine body
–cervix
–vagina
–Vulva
–clitoris
– mammary gland (accessory reproductive organs)
47
•Female reproductive tracts of various farm animals are similar,
but differ primarily in the shape of the uterus and cervix.
•Female reproductive tract consists of
–two ovaries
–two oviducts
–two uterine horns
–uterine body
–cervix
–vagina
–Vulva
–clitoris
– mammary gland (accessory reproductive organs)
47
Female Tract
Female reproductive system
•Ovaries
–Produce egg(oocyte) &
hormones
•Oviducts
–Site of fertilization
–Transport embryos to
uterus
–Carry the eggs from the
ovaries to the uterus
•Uterus
–Site of embryonic
development during
gestation
•Ovaries
–Produce egg(oocyte) &
hormones
•Oviducts
–Site of fertilization
–Transport embryos to
uterus
–Carry the eggs from the
ovaries to the uterus
•Uterus
–Site of embryonic
development during
gestation
•Cervix
–Connects uterus and
vagina
–Serve as barrier during
pregnancy
•Vagina
–Female organ of
copulation at mating
–birth canal
•Vulva
–External opening of
reproductive system
–Connects uterus and
vagina
–Serve as barrier during
pregnancy
•Vagina
–Female organ of
copulation at mating
–birth canal
•Vulva
–External opening of
reproductive system
Cow FRT
General functions of female reproductive system
Receive the penis of the male animal (accommodation)
Involve production of oocytes
Allow the germ cells of the male to combine with those of
females (fertilization)
Provision of an environment for growth and nutrition of the
fetus (pregnancy)
Give birth at an appropriate time (parturition), and to
continue the nutritional function through lactation.
Production of hormones
Receive the penis of the male animal (accommodation)
Involve production of oocytes
Allow the germ cells of the male to combine with those of
females (fertilization)
Provision of an environment for growth and nutrition of the
fetus (pregnancy)
Give birth at an appropriate time (parturition), and to
continue the nutritional function through lactation.
Production of hormones
Ovaries
Two oval shaped primary organs located its respective right
or left kidney.
It is suspended from the dorsal wall of the abdomen by a
reflection of the peritoneum, the mesovarium.
The entire ovary is enclosed by a layer of condensed fibrous
tissue called the tunica albuginea.
It is covered with germinal epithelium
Ovary consists of cortex and medulla.
The cortex consists of ovarian follicles & interstitium/stroma in
between them.
The medulla contains abundant blood vessel in loose connective
tissue, blood vessels & nerves.
Two oval shaped primary organs located its respective right
or left kidney.
It is suspended from the dorsal wall of the abdomen by a
reflection of the peritoneum, the mesovarium.
The entire ovary is enclosed by a layer of condensed fibrous
tissue called the tunica albuginea.
It is covered with germinal epithelium
Ovary consists of cortex and medulla.
The cortex consists of ovarian follicles & interstitium/stroma in
between them.
The medulla contains abundant blood vessel in loose connective
tissue, blood vessels & nerves.
Ovarian Follicles
•Follicle (hollow ball of cells) is the basic functional unit of
ovary, derived from germinal epithelium cells of ovary.
•Composed of oocyte (egg cells) in various stages of
development, theca cells and granulosa cells.
•The primary role of follicle is oocyte support during growth &
maturation phase.
• When the follicle rupture, it becomes corpus luteum.
•Secrete estrogens that function for:-
₋growth and repair of uterine lining
₋regulation of monthly female cycle
₋female sexual features
₋maintenance of bone and muscle
•Follicle (hollow ball of cells) is the basic functional unit of
ovary, derived from germinal epithelium cells of ovary.
•Composed of oocyte (egg cells) in various stages of
development, theca cells and granulosa cells.
•The primary role of follicle is oocyte support during growth &
maturation phase.
• When the follicle rupture, it becomes corpus luteum.
•Secrete estrogens that function for:-
₋growth and repair of uterine lining
₋regulation of monthly female cycle
₋female sexual features
₋maintenance of bone and muscle
Ovary
Ovarian physiology
The two main role of ovaries are
Gamete production (eggs) by oogenesis
Secrete estrogen (hormone) and progesterone
The ovarian function including
₋follicular maturation
₋ovulation and
₋corpus luteum formation
The two main role of ovaries are
Gamete production (eggs) by oogenesis
Secrete estrogen (hormone) and progesterone
The ovarian function including
₋follicular maturation
₋ovulation and
₋corpus luteum formation
Follicular development
•Folliculogenesis is the process in which a recruited
primordial follicle grows & develops into a graafian follicle
with the potential to either to
₋ovulate its egg into the oviduct to be fertilized or
₋die by atresia.
•The follicles contain immature eggs and are present in the
ovaries at birth.
•One or sometimes more of the follicles are selected for further
growth and maturation.
•Folliculogenesis starts from primordial follicle=>primary follicle
=> secondary follicle=> graafian follicle.
•Folliculogenesis is the process in which a recruited
primordial follicle grows & develops into a graafian follicle
with the potential to either to
₋ovulate its egg into the oviduct to be fertilized or
₋die by atresia.
•The follicles contain immature eggs and are present in the
ovaries at birth.
•One or sometimes more of the follicles are selected for further
growth and maturation.
•Folliculogenesis starts from primordial follicle=>primary follicle
=> secondary follicle=> graafian follicle.
Primordial follicle
₋At birth, the ovaries contain immature primordial follicle
which contain immature primary oocyte.
₋Forms single layer of flattened (squamous) granulosa cells,
and a basal lamina.
₋Contain a single oocyte that is surrounded by a single layer
of granulose cells.
₋Granulosa cells are derived from superficial epithelium
Primary follicle
₋Consists of a single cuboidal granulosa cells that surrounds
the primary oocyte.
₋Zona pellucida forms around the oocyte, separating it around
the forming granulosa.
₋Stroma cells around the oocyte forms theca cell.
₋At birth, the ovaries contain immature primordial follicle
which contain immature primary oocyte.
₋Forms single layer of flattened (squamous) granulosa cells,
and a basal lamina.
₋Contain a single oocyte that is surrounded by a single layer
of granulose cells.
₋Granulosa cells are derived from superficial epithelium
Primary follicle
₋Consists of a single cuboidal granulosa cells that surrounds
the primary oocyte.
₋Zona pellucida forms around the oocyte, separating it around
the forming granulosa.
₋Stroma cells around the oocyte forms theca cell.
Secondary (growing) follicle
•2 to 10 layers of cuboidal or low columnar cells that form a
stratified epithelium surrounds primary oocyte.
•Theca layer formation (theca interna & theca externa)
•Theca cells produce androgen under LH stimulation.
•Granulosa cells secrete fluid once stimulated by FSH.
•Granulosa cells convert androgen to estrogen under FSH
stimulation then E2 (Estradiol) released in to the fluid and blood.
Graafian (tertiary) follicle
•Can be defined structurally as a heterogeneous family of
relatively large follicles.
•Characterized by a cavity or antrum containing a fluid called
follicular fluid or liquor folliculi.
•The characteristic structural unit of all graafian follicle is the
antrum.
•follicle cell+ developing oocyte = graafian follicle
•2 to 10 layers of cuboidal or low columnar cells that form a
stratified epithelium surrounds primary oocyte.
•Theca layer formation (theca interna & theca externa)
•Theca cells produce androgen under LH stimulation.
•Granulosa cells secrete fluid once stimulated by FSH.
•Granulosa cells convert androgen to estrogen under FSH
stimulation then E2 (Estradiol) released in to the fluid and blood.
Graafian (tertiary) follicle
•Can be defined structurally as a heterogeneous family of
relatively large follicles.
•Characterized by a cavity or antrum containing a fluid called
follicular fluid or liquor folliculi.
•The characteristic structural unit of all graafian follicle is the
antrum.
•follicle cell+ developing oocyte = graafian follicle
Graafian follicle….
•Is the follicular stage after first meiotic division of the oocyte
and but before ovulation.
•Its theca layer are theca externa which is outer and more
fibrous cell layer and the inside is theca interna layer which is
a secretory layer.
•Its granulosa cells act as nurse cells, providing nutrients to
the oocyte via gap junctions that are essential for oocyte
growth.
•Tertiary follicle oocyte is acentrally positioned on the
cumulus oophorus, a hillock (mound) of granulosa cells,
located at one side of the antrum.
•Is the follicular stage after first meiotic division of the oocyte
and but before ovulation.
•Its theca layer are theca externa which is outer and more
fibrous cell layer and the inside is theca interna layer which is
a secretory layer.
•Its granulosa cells act as nurse cells, providing nutrients to
the oocyte via gap junctions that are essential for oocyte
growth.
•Tertiary follicle oocyte is acentrally positioned on the
cumulus oophorus, a hillock (mound) of granulosa cells,
located at one side of the antrum.
•The oocyte surrounded in the tertiary follicle is enveloped
by zona pellucida and corona radiata.
•The granulosa cells surrounding and in immediate contact
with the potential ovum are termed the corona radiata.
•Both theca interna and granulosa cells are involved in
production of estrogen.
•The theca cells respond for LH by secreting androgen
hormone whereas granulosa cells convert androgen to
estrogen in response to FSH stimulation.
–granulosa cells produce inhibin to as feedback
mechanism to control release of FSH form pituitary
•Estrogen is naturally mitogenic so it stimulates proliferation
of granulosa cells so that many layers of granulosa cells is
formed.
by zona pellucida and corona radiata.
•The granulosa cells surrounding and in immediate contact
with the potential ovum are termed the corona radiata.
•Both theca interna and granulosa cells are involved in
production of estrogen.
•The theca cells respond for LH by secreting androgen
hormone whereas granulosa cells convert androgen to
estrogen in response to FSH stimulation.
–granulosa cells produce inhibin to as feedback
mechanism to control release of FSH form pituitary
•Estrogen is naturally mitogenic so it stimulates proliferation
of granulosa cells so that many layers of granulosa cells is
formed.
•Oocytes (egg cells) develop
within follicles
•Stages of follicular
development
–Primordial follicle
•Single layer of squamous cells
around the oocyte
–Primary follicle
•Layers of cuboidal granulosa
cells around the oocyte
•Granulosa cells secrete
estrogens
within follicles
•Stages of follicular
development
–Primordial follicle
•Single layer of squamous cells
around the oocyte
–Primary follicle
•Layers of cuboidal granulosa
cells around the oocyte
•Granulosa cells secrete
estrogens
–Secondary follicle
•Antral cavity
forms
–Graafian follicle
•Follicle mature
ready to ovulate
oocyte
–Ovulation
•Follicle ruptures
releasing oocyte
Ovulation is the release of secondary oocyte
•Antral cavity
forms
–Graafian follicle
•Follicle mature
ready to ovulate
oocyte
–Ovulation
•Follicle ruptures
releasing oocyte
Ovulation is the release of secondary oocyte
Corpus Luteum
•After ovulation, collapsed follicle
becomes a corpus luteum
–Corpus Luteum secretes:-
•Progesterone – completes the
preparation of uterine lining
•Estrogens – work with
progesterone
•Relaxin – relaxes uterine muscles
and pubic symphysis
•Inhibin – decreases secretion of
FSH and LH
•Corpus albicans is a white scar
tissue left after the corpus luteum
dies.
•After ovulation, collapsed follicle
becomes a corpus luteum
–Corpus Luteum secretes:-
•Progesterone – completes the
preparation of uterine lining
•Estrogens – work with
progesterone
•Relaxin – relaxes uterine muscles
and pubic symphysis
•Inhibin – decreases secretion of
FSH and LH
•Corpus albicans is a white scar
tissue left after the corpus luteum
dies.
Follicle regression
•Considerable atresia (regression) of the many primordial
follicles occurs by birth and throughout the reproductive life
of the female.
•Growth of some number of primordial follicles does occur
after birth & before puberty but these never reach the
graafian follicle stage.
•The growth of follicle that occurs before puberty is not
hormone related and is probably controlled by an unknown
intraovarian factor.
•The formation of Graafian follicles is hormone dependent and
begins at puberty when LH and FSH level begin to rise and
fall with each estrous cycle.
•Considerable atresia (regression) of the many primordial
follicles occurs by birth and throughout the reproductive life
of the female.
•Growth of some number of primordial follicles does occur
after birth & before puberty but these never reach the
graafian follicle stage.
•The growth of follicle that occurs before puberty is not
hormone related and is probably controlled by an unknown
intraovarian factor.
•The formation of Graafian follicles is hormone dependent and
begins at puberty when LH and FSH level begin to rise and
fall with each estrous cycle.
Oogenesis
•Oogenesis is the process by which oocytes are formed
from oogonia which occurs in the ovaries.
•Starts before birth.
•Oogonia (formed from primordial germ cells) are present in
the cortex of ovary.
•Oogonia are produced before birth then it forms primary
oocytes contained within primordial follicle.
•Oogenesis completed after fertilization.
•Oogenesis is the process by which oocytes are formed
from oogonia which occurs in the ovaries.
•Starts before birth.
•Oogonia (formed from primordial germ cells) are present in
the cortex of ovary.
•Oogonia are produced before birth then it forms primary
oocytes contained within primordial follicle.
•Oogenesis completed after fertilization.
Ovulation
•Ovulation is the process in which a mature egg is released
from the ovary into the oviduct and is controlled by LH.
•After ovulation, the mature follicle that released the oocyte
become corpus luteum (yellow body).
•Concomitantly, the lining of the uterus is thickened to be
able to receive a fertilized egg.
•The oocyte will become available to be fertilized and if
fertilized by sperm and implants in the endometruim, the
hormonal change transforms the CL into the steroid factory,
producing much progesterone, that maintains pregnancy.
•If fertilization doesn’t occur, the CL involutes in to corpus
albicans that appears as a cloud like pink scar.
72
•Ovulation is the process in which a mature egg is released
from the ovary into the oviduct and is controlled by LH.
•After ovulation, the mature follicle that released the oocyte
become corpus luteum (yellow body).
•Concomitantly, the lining of the uterus is thickened to be
able to receive a fertilized egg.
•The oocyte will become available to be fertilized and if
fertilized by sperm and implants in the endometruim, the
hormonal change transforms the CL into the steroid factory,
producing much progesterone, that maintains pregnancy.
•If fertilization doesn’t occur, the CL involutes in to corpus
albicans that appears as a cloud like pink scar.
72
•Ovulation in almost all animals is spontaneous in which
ovulation occurs due to immediate effect of hormones
except in queen which is induced ovulator.
73
ovulation occurs due to immediate effect of hormones
except in queen which is induced ovulator.
73
Corpus luteum formation and regression
•Formation of the CL involves luteinization of the granulosa,
by which the granulosa is converted from E2 secretion to
progesterone secretion.
•Maintenance of the CL is provided by LH derived from the LH
surge and by the basal circulating levels of LH.
•PGF2a is released by the non-pregnant uterus about 14
days after ovulation and is considered to be the natural
luteolytic substance (causes regression of the CL).
•Formation of the CL involves luteinization of the granulosa,
by which the granulosa is converted from E2 secretion to
progesterone secretion.
•Maintenance of the CL is provided by LH derived from the LH
surge and by the basal circulating levels of LH.
•PGF2a is released by the non-pregnant uterus about 14
days after ovulation and is considered to be the natural
luteolytic substance (causes regression of the CL).
Ovulation rates by species
Cow - 1 egg per estrus
Ewe - 1 to 3 eggs per estrus
Sow - 10 to 20 eggs per estrus
Mare - 1 egg per estrus
Hen - Approx. 28 eggs per month
Cow - 1 egg per estrus
Ewe - 1 to 3 eggs per estrus
Sow - 10 to 20 eggs per estrus
Mare - 1 egg per estrus
Hen - Approx. 28 eggs per month
Regulation of ovarian function
•The processes of follicular development, ovulation, and formation
& function of the corpus luteum are controlled by FSH and LH.
•Before the onset of puberty the ovaries are quiescent (at rest),
and the cortex of each ovary contains only immature follicles.
•Puberty begins with pulsatile secretion of GnRH from
the hypothalamus then LH and FSH secreted from pituitary.
•FSH is primarily responsible for stimulating the growing of ovarian
follicle.
•LH main function is to cause ovulation and it causes the formation
of corpus luteum.
•Increasing secretion of gonadotropins leads to increasing
production of estrogens by the ovaries.
•The processes of follicular development, ovulation, and formation
& function of the corpus luteum are controlled by FSH and LH.
•Before the onset of puberty the ovaries are quiescent (at rest),
and the cortex of each ovary contains only immature follicles.
•Puberty begins with pulsatile secretion of GnRH from
the hypothalamus then LH and FSH secreted from pituitary.
•FSH is primarily responsible for stimulating the growing of ovarian
follicle.
•LH main function is to cause ovulation and it causes the formation
of corpus luteum.
•Increasing secretion of gonadotropins leads to increasing
production of estrogens by the ovaries.
Estrous cycle
•Estrous cycle is reproductive cycle of female, defined as the
period from one estrus to the next.
•It comprises the requiring physiological changes that are
induced by reproductive hormones.
•Repetitive cycle occurring and does not occur when there is
pregnancy or anestrous phases but continue until death .
₋ Estrus (heat) is time a female animal is receptive to mating/ bred.
•Consists of sequence physiological and behavioral events.
•The main reproductive cycle of other species females of non-
primate vertebrates.
•Estrous cycle is reproductive cycle of female, defined as the
period from one estrus to the next.
•It comprises the requiring physiological changes that are
induced by reproductive hormones.
•Repetitive cycle occurring and does not occur when there is
pregnancy or anestrous phases but continue until death .
₋ Estrus (heat) is time a female animal is receptive to mating/ bred.
•Consists of sequence physiological and behavioral events.
•The main reproductive cycle of other species females of non-
primate vertebrates.
8
Proestrus Estrus
Metestrus
Diestrus
Stages of estrous
Proestrus Estrus
Metestrus
Diestrus
Stages of estrous
Proestrus
•Period for preparation of sexual activity.
•Period between the regression of the CL of the previous cycle
and start of onset estrus.
•Begins when P4 declines and ends at onset of estrus.
•It is period of major endocrine transition
oP4 dominance to E2 dominance
oFSH and LH responsible
•Enlargement of ovarian follicle with oocyte
•Estrogen absorbed in blood stream to vascularize the
reproductive tract and genitalia.
•Period for preparation of sexual activity.
•Period between the regression of the CL of the previous cycle
and start of onset estrus.
•Begins when P4 declines and ends at onset of estrus.
•It is period of major endocrine transition
oP4 dominance to E2 dominance
oFSH and LH responsible
•Enlargement of ovarian follicle with oocyte
•Estrogen absorbed in blood stream to vascularize the
reproductive tract and genitalia.
Estrus
•Period of sexual receptivity or readiness to accept male.
•Large increase in estrogen which in turn stimulate LHRH.
•The presence of high estrogen produces behavioral signs of
heat such as
₋Mounting and willingness to stand while mounted by other
₋bellowing and red & swollen vulva.
₋clear mucus discharge from vulva, and general increase of
activity to permit mating.
•FSH decrease due to estrogen and Inhibin
•During/shortly after estrus, ovulation occurs due to major
surge in LH.
–LH level increase due to LHRH
–Estrus stops once ovulation occur
•Period of sexual receptivity or readiness to accept male.
•Large increase in estrogen which in turn stimulate LHRH.
•The presence of high estrogen produces behavioral signs of
heat such as
₋Mounting and willingness to stand while mounted by other
₋bellowing and red & swollen vulva.
₋clear mucus discharge from vulva, and general increase of
activity to permit mating.
•FSH decrease due to estrogen and Inhibin
•During/shortly after estrus, ovulation occurs due to major
surge in LH.
–LH level increase due to LHRH
–Estrus stops once ovulation occur
Metestrus
•The early postovulatory period
•CL development begins under the influence of LH
•Increase progesterone, decrease in estrogen
•Endometrial lining thickens and uterine muscle shows
increased development.
•Ovulation occurs during metestrus in cattle & goats
Diestrus
•Period of mature luteal activity
•Relatively short period of time
•Sustained luteal secretion of P4
•Here, the body system assumes pregnancy
•The early postovulatory period
•CL development begins under the influence of LH
•Increase progesterone, decrease in estrogen
•Endometrial lining thickens and uterine muscle shows
increased development.
•Ovulation occurs during metestrus in cattle & goats
Diestrus
•Period of mature luteal activity
•Relatively short period of time
•Sustained luteal secretion of P4
•Here, the body system assumes pregnancy
Characteristics of estrous cycles
Cow Ewe Sow Mare
Estrous cycle (days) 21 17 21 21
Proestrus (days) 3-4 2-3 3-4 2-3
Estrus 12-18 hr 24-36 hr 48-72 hr 4-8 days
Metestrus (days) 3-4 2-3 2-3 2-3
Diestrus (days) 10-14 10-12 11-13 10-12
Cow Ewe Sow Mare
Estrous cycle (days) 21 17 21 21
Proestrus (days) 3-4 2-3 3-4 2-3
Estrus 12-18 hr 24-36 hr 48-72 hr 4-8 days
Metestrus (days) 3-4 2-3 2-3 2-3
Diestrus (days) 10-14 10-12 11-13 10-12
Animals classified according to estrous cycle
Polyestrous animals: Animals with uniform distribution of
estrous cycles which occurs regularly throughout the year.
Example: Cow and Sow
Seasonally polyestrous animals: Animals that have
multiple estrous cycles only during certain periods of the
year (horses, sheep, goats, cats).
• Seasonal with decreasing light => ewe and doe
• Seasonal with increasing daylight=> mare and queen
–Monestrous animals: animals that have one estrous cycle
per year and their period of estrus lasts for several days.
» Example: bitch
Polyestrous animals: Animals with uniform distribution of
estrous cycles which occurs regularly throughout the year.
Example: Cow and Sow
Seasonally polyestrous animals: Animals that have
multiple estrous cycles only during certain periods of the
year (horses, sheep, goats, cats).
• Seasonal with decreasing light => ewe and doe
• Seasonal with increasing daylight=> mare and queen
–Monestrous animals: animals that have one estrous cycle
per year and their period of estrus lasts for several days.
» Example: bitch
Female reproductive parameters in domestic animals
Cow mare ewe doe sow bitch queen
Age of puberty
(month)
10 – 12
breed
difference
15 – 24
Seasonal
effect
7 - 10 6 - 8 5 - 8 6 - 12 5 - 12
Age of sex
maturation
30 36 10
8(if born in
early years)
10 5 - 12 6 - 12
Type of estrous
cycle
Poly estrous
Seasonal
poly estrous
Seasonal
poly estrous
Seasonal
poly estrous
poly estrous monestrous polyestrous
Length of
estrous cycle
21 day 22 day 17 days 21 days 21 days 15 -65 weeks
2 – 3 weeks
(if no mated)
Duration of
estrus
24 (hours) 4 -7 days 36 hours
18 – 36
hours
48-72 hours 9 -10 days 3 -6 days
Optimal breed
after onset of
estrus
10 -16 hrs 48 -72 hrs 18 – 24 hrs 24 – 36 hrs 12 – 30 48 -96 During estrus
Time of
ovulation
4 -16 after
estrous
24 -48 hrs
before end
of estrous
24 hours
after onset
estrous
12 – 36
Hrs after
onset
estrous
24 – 42
hrs after
onset
estrous
1 -3 day
after onset
estrous
25 – 50 hrs
after coitus
Mechanism of
ovulation
spontaneous spontaneous spontaneous spontaneous spontaneous spontaneous induced
Ovulation rate
(number of ova)
1 1 1 -2 2 -3 10 -20 6 -8 4
Cow mare ewe doe sow bitch queen
Age of puberty
(month)
10 – 12
breed
difference
15 – 24
Seasonal
effect
7 - 10 6 - 8 5 - 8 6 - 12 5 - 12
Age of sex
maturation
30 36 10
8(if born in
early years)
10 5 - 12 6 - 12
Type of estrous
cycle
Poly estrous
Seasonal
poly estrous
Seasonal
poly estrous
Seasonal
poly estrous
poly estrous monestrous polyestrous
Length of
estrous cycle
21 day 22 day 17 days 21 days 21 days 15 -65 weeks
2 – 3 weeks
(if no mated)
Duration of
estrus
24 (hours) 4 -7 days 36 hours
18 – 36
hours
48-72 hours 9 -10 days 3 -6 days
Optimal breed
after onset of
estrus
10 -16 hrs 48 -72 hrs 18 – 24 hrs 24 – 36 hrs 12 – 30 48 -96 During estrus
Time of
ovulation
4 -16 after
estrous
24 -48 hrs
before end
of estrous
24 hours
after onset
estrous
12 – 36
Hrs after
onset
estrous
24 – 42
hrs after
onset
estrous
1 -3 day
after onset
estrous
25 – 50 hrs
after coitus
Mechanism of
ovulation
spontaneous spontaneous spontaneous spontaneous spontaneous spontaneous induced
Ovulation rate
(number of ova)
1 1 1 -2 2 -3 10 -20 6 -8 4
I. Follicular phase
₋Period from regression of CL to ovulation
₋Short phase- only 20% of the cycle
₋Preovulatory follicle
₋Estrogen is dominant hormone
₋This phase ends at the time of ovulation.
₋Proestrus + estrus
II. Luteal phase
₋Period from ovulation to CL regression
₋ long phase- 80% of the cycle
₋ Corpora lutea
₋Progesterone is dominant hormone
₋Metestrus + diestrus
Phase of estrous cycle
₋Period from regression of CL to ovulation
₋Short phase- only 20% of the cycle
₋Preovulatory follicle
₋Estrogen is dominant hormone
₋This phase ends at the time of ovulation.
₋Proestrus + estrus
II. Luteal phase
₋Period from ovulation to CL regression
₋ long phase- 80% of the cycle
₋ Corpora lutea
₋Progesterone is dominant hormone
₋Metestrus + diestrus
Phase of estrous cycle
Try it
Why the body(corpus) of uterus is larger in mare as
compared to sow and bitch?
What is the importance of cervical goblet cell secretions by
during pregnancy in cow?
What is the function of myometrium during pregnancy and
parturition?
How (pathway) PGF2a transport from uterus to the ovary to
regress CL if pregnancy doesn’t occur?
Why the body(corpus) of uterus is larger in mare as
compared to sow and bitch?
What is the importance of cervical goblet cell secretions by
during pregnancy in cow?
What is the function of myometrium during pregnancy and
parturition?
How (pathway) PGF2a transport from uterus to the ovary to
regress CL if pregnancy doesn’t occur?
Transport of oocyte and spermatozoa
•At ovulation, the fimbriae of the uterine tubes (oviduct) are
in close contact with the ovaries.
•The contractile activity of the fimbriae directs the shed
oocyte into the funnel‐shaped infundibulum.
•The oocyte directed toward the uterus by cilia of oviduct and
by contraction of smooth muscle motility.
•The ejaculated & capacitated spermatozoa are transported
to the uterine tubes to fertilize the ova by
–increased motility within the uterus caused by the
release of oxytocin at the time of coitus and
–the presence of prostaglandins in semen
•At ovulation, the fimbriae of the uterine tubes (oviduct) are
in close contact with the ovaries.
•The contractile activity of the fimbriae directs the shed
oocyte into the funnel‐shaped infundibulum.
•The oocyte directed toward the uterus by cilia of oviduct and
by contraction of smooth muscle motility.
•The ejaculated & capacitated spermatozoa are transported
to the uterine tubes to fertilize the ova by
–increased motility within the uterus caused by the
release of oxytocin at the time of coitus and
–the presence of prostaglandins in semen
Fertilization
•Fertilization is the formation of a diploid zygote from the
fusion haploid ovum and sperm to initiate the development
of new individual/offspring.
•After the male ejaculate sperm into the vagina during coitus,
few sperms are transported toward the fallopian tubes.
•The transport of sperm aided by contraction of uterus and
fallopian tubes then fertilization takes place in the ampulla of
the oviduct.
•Spermatozoa don’t fertilized ova unless they undergone a
period of incubation in the female tract.
•This new phenomenon is called capacitation.
89
•Fertilization is the formation of a diploid zygote from the
fusion haploid ovum and sperm to initiate the development
of new individual/offspring.
•After the male ejaculate sperm into the vagina during coitus,
few sperms are transported toward the fallopian tubes.
•The transport of sperm aided by contraction of uterus and
fallopian tubes then fertilization takes place in the ampulla of
the oviduct.
•Spermatozoa don’t fertilized ova unless they undergone a
period of incubation in the female tract.
•This new phenomenon is called capacitation.
89
•Capacitation is physiochemical change due to vaginal and
uterine secretions.
•Capacitation induce further maturation through causing
molecular change on plasma membrane of sperm that brings
hyper motility.
•Once sperm reach to the ovulated ovum at the ampulla of the
oviduct, it travels through an outer layer(corona radiata) to
reach the zona pellucida (extracellular matrix of the egg).
•Then after fertilization is penetration of zona pellucida by
the spermatozoon with acrosomal proteolytic enzymes
(hyaluronidase and acrosin) => acrosomal reaction.
•The zona reaction occurs after penetration zona pellucida
and protects the oocyte from further penetration (block to
polyspermy) by other spermatozoa as an egg must be
fertilized by a single sperm only.
uterine secretions.
•Capacitation induce further maturation through causing
molecular change on plasma membrane of sperm that brings
hyper motility.
•Once sperm reach to the ovulated ovum at the ampulla of the
oviduct, it travels through an outer layer(corona radiata) to
reach the zona pellucida (extracellular matrix of the egg).
•Then after fertilization is penetration of zona pellucida by
the spermatozoon with acrosomal proteolytic enzymes
(hyaluronidase and acrosin) => acrosomal reaction.
•The zona reaction occurs after penetration zona pellucida
and protects the oocyte from further penetration (block to
polyspermy) by other spermatozoa as an egg must be
fertilized by a single sperm only.
•The fusion of the nucleus (intermingling of chr.) of both
gametes leads to formation of zygote soon after fusion of
plasma membrane of gametes.
•A series of morphological, physiological & molecular changes
occur in the egg in response to fusion leads activation of egg.
•Zygotes usually remain in the uterine tube for 3–4 days before
being transferred to the uterus.
gametes leads to formation of zygote soon after fusion of
plasma membrane of gametes.
•A series of morphological, physiological & molecular changes
occur in the egg in response to fusion leads activation of egg.
•Zygotes usually remain in the uterine tube for 3–4 days before
being transferred to the uterus.
Implantation and Placentation
The mammalian ovum (blastocyst) is small and can grow to a
limited extent only since the food supplied in the developing
embryo is not sufficient.
Implantation is the process by which an blastocyst
–attaches to the endometrial wall and
–penetrate first the epithelium and then
–penetrate further to the circulatory system of the dam to
form the placenta.
•Implantation of the embryo occurs when it becomes fixed in
position and forms a physical & functional contact with the
uterus.
•Implantation occurs 14-49 days after fertilization though there
is species variation.
93
The mammalian ovum (blastocyst) is small and can grow to a
limited extent only since the food supplied in the developing
embryo is not sufficient.
Implantation is the process by which an blastocyst
–attaches to the endometrial wall and
–penetrate first the epithelium and then
–penetrate further to the circulatory system of the dam to
form the placenta.
•Implantation of the embryo occurs when it becomes fixed in
position and forms a physical & functional contact with the
uterus.
•Implantation occurs 14-49 days after fertilization though there
is species variation.
93
The placenta is a foetomaternal composite structure formed
by the association of
₋embryo and
₋extra embryonic membrane with uterine tissue for
exchange of food materials, oxygen and waste
materials.
For the formation of placenta foetal part (chorio-allantoic m/m)
and maternal part (endometrium) are participated.
The placenta growth throughout pregnancy
The extra embryonic membrane structure consists of chorion,
allantois, and amnion.
by the association of
₋embryo and
₋extra embryonic membrane with uterine tissue for
exchange of food materials, oxygen and waste
materials.
For the formation of placenta foetal part (chorio-allantoic m/m)
and maternal part (endometrium) are participated.
The placenta growth throughout pregnancy
The extra embryonic membrane structure consists of chorion,
allantois, and amnion.
Function of placenta
1.Supply nutrient to the growing fetus from mothers blood.
2.Site of production of important hormones of pregnancy.
In small quantity it produces estrogen, progesterone &
relaxin.
95
1.Supply nutrient to the growing fetus from mothers blood.
2.Site of production of important hormones of pregnancy.
In small quantity it produces estrogen, progesterone &
relaxin.
95
Pregnancy
•Pregnancy is the condition of the female in which unborn
young are contained within the body.
•Its length is frequently known as the gestation period,
extending from fertilization through birth.
•Pregnancy begins with date of fertilization and ends with
date of parturition, and includes the essential aspects of
implantation and placentation.
•Pregnancy is maintained as a result of the predominance of
progesterone.
•During gestation, P4 is produced by the placenta and CL
though the contribution varies among species.
•Pregnancy is the condition of the female in which unborn
young are contained within the body.
•Its length is frequently known as the gestation period,
extending from fertilization through birth.
•Pregnancy begins with date of fertilization and ends with
date of parturition, and includes the essential aspects of
implantation and placentation.
•Pregnancy is maintained as a result of the predominance of
progesterone.
•During gestation, P4 is produced by the placenta and CL
though the contribution varies among species.
Stages of prenatal life
1.First trimester (1-3 months) = zygote
2.Second trimester(4-6 months) = embryo
3.Third trimester(7-9 months)= fetus
97
1.First trimester (1-3 months) = zygote
2.Second trimester(4-6 months) = embryo
3.Third trimester(7-9 months)= fetus
97
Maternal Recognition of Pregnancy
•In a conceptive cycle, there is a need for continued production
of progesterone through abrogation of luteolytic mechanism.
•The phenomenon through which this is achieved is known as
maternal recognition of pregnancy (MRP).
•MRP is a process by which an early conceptus (blastocyst)
signals its presence to the maternal system and prevents the
lysis of the CL, thus ensuring a maternal milieu supportive of
pregnancy continuation and is achieved by different agents in
different mammalian species.
•It is interferon tau (IFNτ) in ruminant, estrogen in pig, while it
is human chorionic gonadotropin in human.
•In a conceptive cycle, there is a need for continued production
of progesterone through abrogation of luteolytic mechanism.
•The phenomenon through which this is achieved is known as
maternal recognition of pregnancy (MRP).
•MRP is a process by which an early conceptus (blastocyst)
signals its presence to the maternal system and prevents the
lysis of the CL, thus ensuring a maternal milieu supportive of
pregnancy continuation and is achieved by different agents in
different mammalian species.
•It is interferon tau (IFNτ) in ruminant, estrogen in pig, while it
is human chorionic gonadotropin in human.
•IFNτ acts on the endometrium in a paracrine manner to
prevent luteolysis, thereby maintaining the CL & production
of progesterone.
•Maternal recognition of pregnancy occurs from
–day 12- 25 in cow
–day 9-21 in ewe
–day 11- 12 in sow
–day 11 in humans
•Thus, the communication between the conceptus and the
maternal endometrium in the form of MRP is very crucial for
pregnancy establishment and subsequent events such
as implantation and then placentation.
•What will be the eventual consequence if MRP fails?
prevent luteolysis, thereby maintaining the CL & production
of progesterone.
•Maternal recognition of pregnancy occurs from
–day 12- 25 in cow
–day 9-21 in ewe
–day 11- 12 in sow
–day 11 in humans
•Thus, the communication between the conceptus and the
maternal endometrium in the form of MRP is very crucial for
pregnancy establishment and subsequent events such
as implantation and then placentation.
•What will be the eventual consequence if MRP fails?
Parturition
•Parturition is the physiologic process by which the pregnant
uterus delivers the fetus & fetal membranes from the mother.
•In short, it is the process of giving birth that occurs at the end
of the gestation period.
•Ensuring that parturition goes smoothly is the key to avoiding
serious economic losses as well as maintaining the well-being
of one’s herd.
•Relaxin causes the relaxation of ligaments to enable the birth
canal to enlarge and PGF2α helps to relax the cervix.
•An increase in E
2 for the contraction of uterus besides OT.
101
•Parturition is the physiologic process by which the pregnant
uterus delivers the fetus & fetal membranes from the mother.
•In short, it is the process of giving birth that occurs at the end
of the gestation period.
•Ensuring that parturition goes smoothly is the key to avoiding
serious economic losses as well as maintaining the well-being
of one’s herd.
•Relaxin causes the relaxation of ligaments to enable the birth
canal to enlarge and PGF2α helps to relax the cervix.
•An increase in E
2 for the contraction of uterus besides OT.
101
Stages of parturition
Stage 1
•The first stage of parturition is dilation of the cervix.
•The normal cervix is tightly closed right up until the cervical
plug is completely dissolved.
•Cervical dilation begins some 4 to 24 hours before the
completion of parturition.
•At the end of stage one, there may be some noticeable
behavioral changes such as
–elevation of the tail
–switching of the tail and
–increased mucous discharge.
102
Stage 1
•The first stage of parturition is dilation of the cervix.
•The normal cervix is tightly closed right up until the cervical
plug is completely dissolved.
•Cervical dilation begins some 4 to 24 hours before the
completion of parturition.
•At the end of stage one, there may be some noticeable
behavioral changes such as
–elevation of the tail
–switching of the tail and
–increased mucous discharge.
102
Stage 2
•The second stage of parturition is defined as the delivery of
the fetus.
•It begins with the entrance of the membranes and fetus into
the pelvic canal and ends with the completed birth of the
calf.
•This is where all the action is CLINICALLY, and from a
practical aspect we would define it as the appearance of
membranes or water bag at the vulva.
•So the second stage is the one in which we really are
interested.
•Stage 2 in cattle lasts from 2 to 4 hours
103
•The second stage of parturition is defined as the delivery of
the fetus.
•It begins with the entrance of the membranes and fetus into
the pelvic canal and ends with the completed birth of the
calf.
•This is where all the action is CLINICALLY, and from a
practical aspect we would define it as the appearance of
membranes or water bag at the vulva.
•So the second stage is the one in which we really are
interested.
•Stage 2 in cattle lasts from 2 to 4 hours
103
Stage 3
•The third stage of parturition is the expulsion of the placenta
or fetal membranes.
•In cattle this normally occurs in less than 8-12 hrs.
•The membranes are considered retained if after 12 hours
they have not been shed.
104
•The third stage of parturition is the expulsion of the placenta
or fetal membranes.
•In cattle this normally occurs in less than 8-12 hrs.
•The membranes are considered retained if after 12 hours
they have not been shed.
104
Events of parturition
Terminology
Species Act Offspring
Cows calving calf
Ewes lambing lamb
Sows farrowing piglet
Hens hatching chick
Mares foaling foal
Goats kidding kid
Species Act Offspring
Cows calving calf
Ewes lambing lamb
Sows farrowing piglet
Hens hatching chick
Mares foaling foal
Goats kidding kid
Involution of the uterus
•The physiological process by which the uterus returns to its
non-pregnant regular size after parturition is known as
involution.
•The points of attachment of the fetal placenta to the
endometrium slough, and the exposed endometrium heals by
forming new epithelium.
•In addition to new epithelial growth, myometrium contracts
and the cells shorten.
•In cow, uterine involution takes approximately 30 days after
calving.
•The physiological process by which the uterus returns to its
non-pregnant regular size after parturition is known as
involution.
•The points of attachment of the fetal placenta to the
endometrium slough, and the exposed endometrium heals by
forming new epithelium.
•In addition to new epithelial growth, myometrium contracts
and the cells shorten.
•In cow, uterine involution takes approximately 30 days after
calving.
Lactation
•Lactation is defined as the combined process of milk
secretion & removal and is the final stage of the reproductive
cycle.
• Milk is secreted from a specialized cutaneous gland.
•Milk is unique liquid composed of emulsified lipid globules,
colloidal suspended particles, proteins, CHO, minerals and
vitamins, and water.
•In order for lactation to be successful, prepartum proliferation
of alveolar epithelial cells, differentiation of alveolar cell for
secrete milk, and synthesis & secretion of milk components
are needed.
•Lactation period is the period from birth to dryness of cow.
•Lactation is defined as the combined process of milk
secretion & removal and is the final stage of the reproductive
cycle.
• Milk is secreted from a specialized cutaneous gland.
•Milk is unique liquid composed of emulsified lipid globules,
colloidal suspended particles, proteins, CHO, minerals and
vitamins, and water.
•In order for lactation to be successful, prepartum proliferation
of alveolar epithelial cells, differentiation of alveolar cell for
secrete milk, and synthesis & secretion of milk components
are needed.
•Lactation period is the period from birth to dryness of cow.
Mammary gland
•The mammary gland is the milk secreting structure, which includes
a teat, a duct system and lobes (lobules) of secretary tissue drained
by the duct system.
•Milk synthesis and secretion is achieved by the mammary gland
through specialized sebaceous glands.
•The myoepithelial cells are responsible for contracting in response
to oxytocin resulting in milk release and movement from the
alveoli down the ducts, also known as milk letdown.
Discus how milk is letdown?(Pathway)
•Udder of species
- Sheep and goats: two glands and two teats
-Sow: 12-14 teats and two glands per teat
-Mare: Four glands and only two teats
-Cow: four glands and four teats
109
•The mammary gland is the milk secreting structure, which includes
a teat, a duct system and lobes (lobules) of secretary tissue drained
by the duct system.
•Milk synthesis and secretion is achieved by the mammary gland
through specialized sebaceous glands.
•The myoepithelial cells are responsible for contracting in response
to oxytocin resulting in milk release and movement from the
alveoli down the ducts, also known as milk letdown.
Discus how milk is letdown?(Pathway)
•Udder of species
- Sheep and goats: two glands and two teats
-Sow: 12-14 teats and two glands per teat
-Mare: Four glands and only two teats
-Cow: four glands and four teats
109
Milk ejection reflex
•It is initiated by neuro-endocrine reflex
•Suckling stimulates touch receptors on nipple (teat)
•Impulse from these travels to hypothalamus in the brain then
cause release of oxytocin from posterior pituitary.
•Oxytocin causes smooth muscles around alveoli to contract
and squeeze milk into lactiferous ducts, lactiferous sinuses
and into the nipple.
•Estrogen and progestrone causes proliferation of duct tissues
in mammary gland and causes development of lobule,
respectively.
•Prolactin helps in proper lobulo-alvioli development
110
•It is initiated by neuro-endocrine reflex
•Suckling stimulates touch receptors on nipple (teat)
•Impulse from these travels to hypothalamus in the brain then
cause release of oxytocin from posterior pituitary.
•Oxytocin causes smooth muscles around alveoli to contract
and squeeze milk into lactiferous ducts, lactiferous sinuses
and into the nipple.
•Estrogen and progestrone causes proliferation of duct tissues
in mammary gland and causes development of lobule,
respectively.
•Prolactin helps in proper lobulo-alvioli development
110
Colostrums and milk
•Colostrum is a special fluid substance which is secreted by
all female mammals in the last few days of pregnancy and
during the first few days after birth before milk is released.
•Colostrum is highly nutritious (rich in protein, minerals, CHO
and other) and contains antibodies, all substances promotes
growth, development and health in neonates.
•Colostrum is also low in fat, because the digestive systems
of newborn animals cannot handle high amounts of fat.
•Colostrum transfers passive immunity to the offspring from
the dam which helps in priming naïve immune system of the
calf for example.
111
•Colostrum is a special fluid substance which is secreted by
all female mammals in the last few days of pregnancy and
during the first few days after birth before milk is released.
•Colostrum is highly nutritious (rich in protein, minerals, CHO
and other) and contains antibodies, all substances promotes
growth, development and health in neonates.
•Colostrum is also low in fat, because the digestive systems
of newborn animals cannot handle high amounts of fat.
•Colostrum transfers passive immunity to the offspring from
the dam which helps in priming naïve immune system of the
calf for example.
111
•Animals which do not receive colostrum in their first days of
life can experience health problems.
•A newborn calf only has enough energy stores, in the form
of fat and glycogen, to last for approximately 18 hours
without colostrum consumption.
•In addition to being an important part of the diet of a young
animal, colostrum also used in medical research and in
traditional medical treatment in some areas of the world.
112
life can experience health problems.
•A newborn calf only has enough energy stores, in the form
of fat and glycogen, to last for approximately 18 hours
without colostrum consumption.
•In addition to being an important part of the diet of a young
animal, colostrum also used in medical research and in
traditional medical treatment in some areas of the world.
112
Thank you
Tags
Categories
GeneralDownload
Download Slideshow Get the original presentation fileQuick Actions
Statistics
- Views 35
- Slides 113
- Age 457 days
Related Slideshows
22
Pray For The Peace Of Jerusalem and You Will Prosper
RodolfoMoralesMarcuc
45 views
26
Don_t_Waste_Your_Life_God.....powerpoint
chalobrido8
49 views
31
VILLASUR_FACTORS_TO_CONSIDER_IN_PLATING_SALAD_10-13.pdf
JaiJai148317
44 views
14
Fertility awareness methods for women in the society
Isaiah47
41 views
35
Chapter 5 Arithmetic Functions Computer Organisation and Architecture
RitikSharma297999
43 views
5
syakira bhasa inggris (1) (1).pptx.......
ourcommunity56
42 views