Factor affecting growth.ppt

r999d

1. FACTORS AFFECTING THE
GROWTH AND DEVELOPMENT
OF MEAT ANIMALS

2. Genetic Makeup/Breed
•Thegeneticmakeupofanimalsinfluencesthegrowthin
earlierembryoniclifeasdifferencesexistintherateofcell
divisionoftheirembryo
•Thebreedofanimalshassignificantimpactondifferent
parametersofcommercialimportanceandonemainamong
themisdegreeoffatness
•Thefatnesslevelincarcassesvariesgreatlyinanimalshaving
sameweightoragebutdifferentbreed
•e.g.sheepbreedSuffolkandSouthdownslaughteratsame
weight(20kg)have32.9and38.5%fatrespectivelyintheir
carcass

3. •Thephysiologicalageatbirthdependsuponhowagreatpart
ofgrowthisspentinuterus
•Thebirthweightofyoungonesisinfluencebyage,sizeand
nutritionalstatusofmother
•Thelengthofgestationperiod(5monthsforsheepand9
monthsforcattle),sexandnumberofyoungonebornalso
haveimpactonthebirthweight
•Theyoungmothersgenerallyhavelowbirthweightoffspring
comparedtomaturefemalesandsimilarlythebirthweightof
offspringisgreaterfromlargeranimalcomparedtosmaller
mothers
•Therecessivegenesincattlecontrolcertaingrowthfeatures
likedwarfism

4. •Theresponsiblegenecontrolsthelongitudinalbonegrowth
andvertebraldevelopmentinlumbarregion
•Amajorgenehavingsignificantroleinmeatanimalgrowth
andqualityoftheirfleshisthe“Barooroolagene(F)”
•Theselectionofanimalsforimprovedperformancecanbe
donebasedontheheritablecharacterslikebirthweight,
growthfrombirthtoweaning,post-weaninggrowthandfeed
conversionefficiency(Table1.4)
•Thedifferencesinrequirementofessentialnutrientslike
vitaminDandpantothenicacidbydomesticanimalare
geneticallycontrolled
•Oneoftheimportantaspectsofgenevariabilityisthe
determinationoftheendocrinecontrolbalanceofgrowth
anddevelopment

5. •Thegeneticcompatibilitywithenvironmentaffectsthe
apparentvariationingrowth
•Thelambswithhigherrateofthyroidsecretionhaverapid
growthcomparedtothosewithintrinsicallylowrateof
thyroidsecretion
•Theadvancesingeneticsandbreedinghavemadeitpossible
toalterthespecificfeaturesofmuscles
Environmentalconditions
•Theregulationofheatinfarmanimalsisthesubjectofwide
economicimportance
•Thebodytemperatureismaintainedatconstantlevelby
cattleandsheeprequiredforoptimumbiologicalactivity

6. •Thelivingorganismcantoleratenormallyanenvironmental
temperaturelyingintherangeof0-40
o
Cbutsomeanimalare
habitualtoextremeconditionslikebelowfreezingorabove
50
o
C
•Theshortperiodsofevenmoreseverconditionsare
compatiblewithpolaranimalsurvivalastheycantolerate-
80
o
Cbymaintainingtheirbodytemperatures
•Thedevelopmentofanimalsisextendedintheenvironment
oflowtemperaturewhilehightemperaturesretardthe
developmentofun-adaptedlivestock
•Theuniformloworhightemperaturehaslesserimpactonthe
metabolismofanimalsbutvariabletemperatureshavegreater
influence

7. •Ananimalcantolerateprolongexposuretoheatorcold
wavesbyhormonalchangestothesetwostressconditions
•Theanimalshavinglargebodiescanbetterwithstandthelow
temperatureofcoldenvironmentbecauseoflowsurfaceto
volumeratiowhilesmallanimalsduetohighsurfaceto
volumeratiocanefficientlydissipateheatinwarm
environment
•Theyakamongcattlehasheavyandcompactbodywithshort
neckandlegscoveredwiththicklonghairinhabitanttothe
regionsofcoldenvironmentandrarefiedatmosphere
•Thetemperateregionscattlehavesomewhatlesscompact
bodythancoldenvironmentcattle

8. •Thecattleoftropicalregionshaveangularframe,longlegs
andneck,largedewlaptoincreasesurfacetovolumeratio
andhavecoatofshorthair
•Furthermore,thetropicalcattlehavelightlycoloredcoatas
darkcolorationabsorbmoreradiantenergy
•Thetemperateregionanimalswillhavehigherbody
temperaturethantropicalanimalsunderconditionsofheat
stress
•Theheatdisposalmechanismsarelessefficientintemperate
regionanimalsandtheymaintaintheirbodytemperature
throughbehavioralchangeslikevoluntaryrestrictionoffeed
intake,seekingshadeandinactivity

9. •FeedandNutrition
•Thedevelopment,dominanceandsurvivalofallliving
organismaredeterminedbythemostimportantfactorof
findingenoughfoodsofrightkinds
•Themajorproportionoflifetimeofallcoldblooded
animalsandmostofwarmbloodedanimalsisspentdoing
nothing
•Theyspentgreaterpartoftheirlifeineatingwhentheystart
doing
•Thefeedandnutritionfactorsaffectingthegrowthand
developmentofanimalsareplanandqualityofnutrition,
interspeciesinteraction,plantnutritionandmicronutrients

10. •Feedingplanandnutritionalquality
•Thefeedingplanandnutritionalqualityoffeedatanystage
ofanimallifealterthegrowthofanimalingeneralandalso
affectthedevelopmentofdifferentregions,tissuesand
organsdifferentially
•Theanimalofsamebreedandweightwillvaryinformand
compositioniftheyhavedifferentfeedingplansandnutrients
quality
•Thebrainandnervoussystemhavepriorityoverbone,
musclesandfatindevelopmentorderinrelationtoplanof
nutrition
•Thetissuesandbodyregionsareutilizedinreverseorderof
theirmaturityforenergyandproteinsupplytobodyunder
conditionsoflownutrientsdiets

11. •Fatsareutilizedfirstundertheseconditionsfollowedby
proteinsandbonesandthesearefirstdepletedfromthose
regionslatesttomaturity
•Thehighplanofnutritionleadtofastergrowthratecausing
earlieronsetofgrowth’sfatteningphase
•Thefastestgrowinganimalsmaybecomeleanerbyincreasing
theprotein/energyratiosandatveryhighratiothegrowth
ratecanbediminished
•Maleanimalsrequiredietshavinghighprotein/energyratio
thanfemaleandthisrequirementcancausesthedifferencein
carcasscompositionbetweentwosexesfedonsame
protein/energyratiodiet

12. •Therumenmicroflorasubstantiallydeterminedtheintaketo
ruminanttissuessotheyhavequitedifferentrelationshipwith
qualityofdiet
•Ammoniaderivedfromdeaminationofsolubleprotein
enteringtherumenisthemajornitrogensourceformicrobial
synthesisandactivityofthemicro-floraandisdeterminedby
amountofenergyavailabletoanimals
•Theingestedproteinthroughhighproteindietmaybe
excretedasnon-incorporatedammonia
•Thenon-proteinnitrogenoflowproteinfeddietscanbe
convertedtoproteinsandruminantmayvaryintheirprotein
requirementsdependingupontheirrumenmicrofloraand
theseaminoacidscanbesupplementedinthefeedof
ruminants

13. Plane and quality of nutrition
•Differencesintheplaneofnutritionatanyagefromthelate
foetalstageofmaturitynotonlyaltergrowthgenerallybut
alsoaffectthedifferentregions,thedifferenttissuesandthe
variousorgansdifferentially
•Thusanimalsondifferentplanesofnutrition,evenifthey
areofthesamebreedandweight,willdiffergreatlyinform
andcomposition
•Therelationshipoftheruminanttothequalityofthedietis
differentsincetheintakeintothetissuesissubstantially
determinedbytherumenmicroflora
Interactionwithotherspecies
•Ingeneral,therearedefiniteupperandlowerlimitstothe
sizeofanimalwhichacarnivorecanutilize

15. •Themostseriouseffectsofotheranimalspecieson
domesticstock,however,ariseindirectlywhentherateof
naturalincreaseofsmallspecies
•Therabbit,whenintroducedintoAustralia,increasedata
phenomenalrateanddenudedvastareasofthevegetation
uponwhichstockhadpreviouslysubsisted
•Somespecies,ofcourse,arebeneficialtodomesticstock
•Ruminantslargelydependonthemicro-organismsintheir
digestivetracttobreakdownthecelluloseofplantfoods
•Theyarethusequippedtomakeuseofpoor-qualitydiets

16. Soilsandplantgrowth
•Althoughsomeanimalsarecarnivorestheyareultimately
asdependentonplantlifefortheirsustenanceasthe
herbivores
•Foodrepresentsstoredenergyutilizablebyanimalsandit
canbereleasedataratedeterminedbymetabolicneeds
•Themajorultimatesourceofenergyissunlight;anditis
onlyinthePlantKingdomthatamechanismexistsforits
conversionintoastoredform
•Thefertilityofsoilsdependsnotonlyonthechemical
natureoftherocksfromwhichtheyhavebeenformedbut
alsoonparticlesize

17. •Thelatterdetermineshowmuchmoisturesoilswillhold
andforhowlong,andtheavailabilityofitsnutrientsto
plants
•Soilsandclimateaffectplantgrowthqualitativelyaswell
asquantitatively
•Thegrassesoflownitrogencontentdeveloponacidsoils
•Thenitrogencontentofgrassesandlegumesdiminisheson
prolongedexposuretohightemperatures
•Thedigestibilityofplantsmaybealteredartificially
•Theincreasinguseofplantgrowthsubstances,suchas
gibberellicacid,whichincreasestheinternodedistancein
grasses,tendstolowerthenitrogencontentofgrassesand
todecreasedigestibility

18. Trace materials in soils and pastures
•Itisbeingincreasinglyrecognizedthatmanyanimal
ailmentscanbeexplainedonthebasisofdietary
deficienciesorexcessesofbiologicallypotentmaterials
whicharepresentonlyinminutequantitiesinsoilsand
pastures
•Adeficiencyofcobaltinthesoilsofcertainareaswasthe
causeofvariouswastingandnervousdiseasesincattleand
sheepwhichhadbeenknownformanyyearsbysettlers
•Animals,aftergrazingforseveralmonths,wouldlosetheir
appetiteandfinallydieinthemidstofrichpasture
•Copperdeficiencyinhibitstheactionofvariousamine
oxidases,and,thereby,thestructuralintegrityofelastinand
collageninconnectivetissues

19. •Anexcessofmolybdenuminthesoilissaidtoenhance
copperdeficiencyinanimals
•Anexcessofseleniuminterfereswithmetabolismby
displacingsulphurfromtheessential–SHgroupsof
dehydrogenaseenzymes
•Anexcessofpotassium,byinterferingwiththe
accumulationofsodium,alterstheionicbalanceofbody
fluidsandmaycausehypersensitivitytohistamine
•Conditionssuchasgrasstetanyandmilkfever,wherein
themagnesiumorcalciumcontentofbloodserumis
especiallylow

20. •Toxicityinstockmayalsoarisebytheexcessingestionof
traceorganicsubstances
•Somepastures,maycontainsufficientisoflavonesor
flavonesofoestrogenicpotencytoaffectthereproductive
activityofgrazingewes