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