Animal Science IAnimal Science I
Livestock ReproductionLivestock Reproduction
Reproductive TermsReproductive Terms
ParturitionParturition– The process of giving birthThe process of giving birth
GestationGestation– The time an animal is pregnantThe time an animal is pregnant
EstrusEstrus– The time a female animal is receptive to breedingThe time a female animal is receptive to breeding
CastrationCastration– The process of removing a male animal’s testiclesThe process of removing a male animal’s testicles
ParturitionParturition
The signs of approaching parturition can The signs of approaching parturition can be observed.be observed.– Females begin to exhibit nesting behaviorFemales begin to exhibit nesting behavior– They becomes restless and attempt to They becomes restless and attempt to
separate from the herd or flock.separate from the herd or flock.
11stst stage stage– Dilation of cervix and entry of fetus into the cervixDilation of cervix and entry of fetus into the cervix
22ndnd stage stage– Completes the birth of an animal through strong Completes the birth of an animal through strong
uterine contractionsuterine contractions
33rdrd stage stage– Expulsion of afterbirth (placenta) from the uterus. Expulsion of afterbirth (placenta) from the uterus. – If the placenta is retained in can interfere with future If the placenta is retained in can interfere with future
reproduction.reproduction.
GestationGestation
Length varies from 174 days for a sow to Length varies from 174 days for a sow to 337 days for a mare337 days for a mare
The new animal is known as an embryo The new animal is known as an embryo while the organs are forming.while the organs are forming.
After differentiation and until birth the After differentiation and until birth the young animal is a fetus.young animal is a fetus.
EstrusEstrus
Period of heat or estrus are triggered by the Period of heat or estrus are triggered by the hormone estrogen.hormone estrogen.
Ovulation takes place during estrus for ewe, Ovulation takes place during estrus for ewe, sow, mare and some companion animals.sow, mare and some companion animals.
The cat only ovulates after mating.The cat only ovulates after mating.
The number of eggs ovulated varies.The number of eggs ovulated varies.– Cows and mares typically ovulates one egg. Cows and mares typically ovulates one egg. – Dogs, horses, and cats may ovulates several eggs Dogs, horses, and cats may ovulates several eggs
(15 or more) (15 or more)
CastrationCastration
Makes the male animals easier to handleMakes the male animals easier to handleMethods:Methods:– ElastratorElastrator
Stretches a specially made rubber band over the scrotum Stretches a specially made rubber band over the scrotum which will cut off circulation.which will cut off circulation.
– Knife or scalpelKnife or scalpelWith this method bleeding must be stopped and flies With this method bleeding must be stopped and flies controlledcontrolled
– Budizzo clampsBudizzo clampsNo BleedingNo BleedingClamp crushes and severs the cords and blood vessels Clamp crushes and severs the cords and blood vessels going to the testicles.going to the testicles.
Reproductive System of a CowReproductive System of a Cow
Parts of the Female Reproductive Parts of the Female Reproductive SystemSystem
OvariesOvaries– Two organs located near the end of the Two organs located near the end of the
reproductive tract inside the body cavityreproductive tract inside the body cavity– Produce ova called eggsProduce ova called eggs
OviductsOviducts– Two tubes that carry the eggs from the Two tubes that carry the eggs from the
ovaries to the uterus and are also called the ovaries to the uterus and are also called the fallopian tubesfallopian tubes
– Carries eggs from ovaries to uterusCarries eggs from ovaries to uterus
Oviduct of a HenOviduct of a Hen
1.1. InfundidbulumInfundidbulum
2.2. MagnumMagnum
3.3. IsthmusIsthmus
4.4. UterusUterus
5.5. Vagina with Vagina with egg insideegg inside
InfundibulumInfundibulum– Funnel shaped end of each oviduct near the ovaryFunnel shaped end of each oviduct near the ovary– Picks up eggs at ovulation and directs eggs into Picks up eggs at ovulation and directs eggs into
oviductoviduct
UterusUterus– Also called the wombAlso called the womb– Place where the fetus growsPlace where the fetus grows
CervixCervix– Neck of uterusNeck of uterus– Separates the uterus from the vaginaSeparates the uterus from the vagina– Serves as a passageway from sperm to travel Serves as a passageway from sperm to travel
from the vagina to the uterus and also seals from the vagina to the uterus and also seals the uterus during pregnancythe uterus during pregnancy
VaginaVagina– Connects the vulva to the cervixConnects the vulva to the cervix– Receives the male penis and sperm at Receives the male penis and sperm at
breedingbreeding– Serves as a passageway fro urine to be Serves as a passageway fro urine to be
expelledexpelled
VulvaVulva– External opening to female reproductive and External opening to female reproductive and
urinary systemsurinary systems
Livestock and Poultry Male Livestock and Poultry Male Reproductive PartsReproductive Parts
ScrotumScrotum– Saclike part outside livestockSaclike part outside livestock– Holds and protects the testiclesHolds and protects the testicles
SheathSheath– Protects the penis from injuryProtects the penis from injury
Testes or testiclesTestes or testicles– Two oval structures inside the scrotum in Two oval structures inside the scrotum in
livestock and inside the body cavity of poultry livestock and inside the body cavity of poultry on each side of the backboneon each side of the backbone
– Produce sperm and male sex hormonesProduce sperm and male sex hormones
EpididymisEpididymis– Long coiled tube connected to each testicleLong coiled tube connected to each testicle– Stores sperm while they matureStores sperm while they mature
Vas deferensVas deferens– Tube that connect the epididymis to urethraTube that connect the epididymis to urethra
Seminal vesiclesSeminal vesicles– Open to urethraOpen to urethra
Prostrate glandProstrate gland– Near the urethra and bladderNear the urethra and bladder
Cowper’s glandCowper’s gland– Near urethraNear urethra
PenisPenis– Covered by the sheathCovered by the sheath– Part that penetrates the female at breedingPart that penetrates the female at breeding– Deposits semen in female livestockDeposits semen in female livestock– Papilla serve this function in poultryPapilla serve this function in poultry
Accessory male reproductive glandsAccessory male reproductive glands
Produce fluids to protect and carry the Produce fluids to protect and carry the spermsperm– Cowper’s glandCowper’s gland– Prostrate glandProstrate gland– Seminal vesiclesSeminal vesicles
Testicles are removed by castration to Testicles are removed by castration to keep males from breedingkeep males from breeding
Papilla is the organ in Papilla is the organ in male poultry’s cloaca male poultry’s cloaca wall that puts the wall that puts the sperm in the hen’s sperm in the hen’s reproductive tract.reproductive tract.
Poultry Reproductive SystemPoultry Reproductive System
The major difference between livestock The major difference between livestock and poultry reproductive systems is that and poultry reproductive systems is that the embryo of livestock develops inside the embryo of livestock develops inside the female’s body and the poultry embryo the female’s body and the poultry embryo develops outside the body.develops outside the body.
Chickens (domestic birds) have only the Chickens (domestic birds) have only the left ovary and oviduct functional at left ovary and oviduct functional at maturity. maturity. – This is what produces the eggsThis is what produces the eggs– The right ovary and oviduct do not functionThe right ovary and oviduct do not function
The ovary produces the ova (eggs) and The ovary produces the ova (eggs) and hormoneshormones
In poultry eggs the yolk is the ovum.In poultry eggs the yolk is the ovum.
The poultry oviduct has five partsThe poultry oviduct has five parts– VaginaVagina– UterusUterus– IsthmusIsthmus– MagnumMagnum– Infundidbulum Infundidbulum
The vent is the outside opening to the The vent is the outside opening to the poultry reproductive tract.poultry reproductive tract.
The uterus and vagina are part of the egg The uterus and vagina are part of the egg production and egg laying process.production and egg laying process.
Functions of Poultry Reproductive Functions of Poultry Reproductive SystemSystem
OvaryOvary– Produces ova or yolks and hormonesProduces ova or yolks and hormones
InfundidbulumInfundidbulum– The place where fertilization takes placeThe place where fertilization takes place
MagnumMagnum– Secretes the thick egg white or albumenSecretes the thick egg white or albumen
IsthmusIsthmus– Adds the two shell membraneAdds the two shell membrane
UterusUterus– Secretes the thin white, the shell, and the shell Secretes the thin white, the shell, and the shell
pigmentpigment
VaginaVagina– Holds the egg until it is laidHolds the egg until it is laid
OviductOviduct– Serves several functions because it is made up of Serves several functions because it is made up of
several partsseveral partsInfundidbulumInfundidbulumMagnumMagnumIsthmusIsthmusUterusUterusVaginaVagina
CloacaCloaca– Egg passes throughEgg passes through– Semen is deposited here during breedingSemen is deposited here during breeding
VentVent– Place where eggs pass out of the hen’s bodyPlace where eggs pass out of the hen’s body– The outside openingThe outside opening
EggEgg– Function is reproduction but is eaten as food by Function is reproduction but is eaten as food by
humans and wild animalshumans and wild animals
Incubation time for chickens is 21 daysIncubation time for chickens is 21 daysIncubation time for ducks and turkeys is 28 daysIncubation time for ducks and turkeys is 28 days
Types of Breeding SystemsTypes of Breeding Systems
Purebred BreedingPurebred Breeding– Mating a registered purebred male and female Mating a registered purebred male and female
of the same breedof the same breed– Angus X AngusAngus X Angus
CrossbreedingCrossbreeding– Mating a male and female of different breedsMating a male and female of different breeds– Angus X Hereford= Crossbred CalfAngus X Hereford= Crossbred Calf– Crossbred X Purebred= CrossbredCrossbred X Purebred= Crossbred– Crossbred X Crossbred= CrossbredCrossbred X Crossbred= Crossbred
InbreedingInbreeding– Mating closely related animalsMating closely related animals– Brother X SisterBrother X Sister– Son X MotherSon X Mother– Father X DaughterFather X Daughter
LinebreedingLinebreeding– Breeding more distant relatives than Breeding more distant relatives than
inbreedinginbreeding– Can be traced back to one common ancestor Can be traced back to one common ancestor
such as a grandparentsuch as a grandparent– Cousin X CousinCousin X Cousin
Grading upGrading up– Mating a purebred male (sire) to grade or Mating a purebred male (sire) to grade or
unregistered or crossbred female (dam) to unregistered or crossbred female (dam) to improve the herdimprove the herd
– Yorkshire boar X Yorkshire/Hampshire sowYorkshire boar X Yorkshire/Hampshire sow
Hybrid vigorHybrid vigor– The superior traits that come from The superior traits that come from
crossbreeding causing the offspring to have crossbreeding causing the offspring to have traits better than either parenttraits better than either parent