Livestock Reproduction Animal Science I Livestock Reproduction

Reproductive Terms Parturition Gestation Estrus Castration The process of giving birth Gestation The time an animal is pregnant Estrus The time a female animal is receptive to breeding Castration The process of removing a male animal’s testicles

Parturition The signs of approaching parturition can be observed. Females begin to exhibit nesting behavior They becomes restless and attempt to separate from the herd or flock.

1st stage 2nd stage 3rd stage Dilation of cervix and entry of fetus into the cervix 2nd stage Completes the birth of an animal through strong uterine contractions 3rd stage Expulsion of afterbirth (placenta) from the uterus. If the placenta is retained in can interfere with future reproduction.

Gestation Length varies from 174 days for a sow to 337 days for a mare The new animal is known as an embryo while the organs are forming. After differentiation and until birth the young animal is a fetus.

Estrus Period of heat or estrus are triggered by the hormone estrogen. Ovulation takes place during estrus for ewe, sow, mare and some companion animals. The cat only ovulates after mating. The number of eggs ovulated varies. Cows and mares typically ovulates one egg. Dogs, horses, and cats may ovulates several eggs (15 or more)

Castration Makes the male animals easier to handle Methods: Elastrator Stretches a specially made rubber band over the scrotum which will cut off circulation. Knife or scalpel With this method bleeding must be stopped and flies controlled Budizzo clamps No Bleeding Clamp crushes and severs the cords and blood vessels going to the testicles.

Reproductive System of a Cow

Parts of the Female Reproductive System Ovaries Two organs located near the end of the reproductive tract inside the body cavity Produce ova called eggs

Oviducts Two tubes that carry the eggs from the ovaries to the uterus and are also called the fallopian tubes Carries eggs from ovaries to uterus

Oviduct of a Hen Infundidbulum Magnum Isthmus Uterus Vagina with egg inside

Infundibulum Funnel shaped end of each oviduct near the ovary Picks up eggs at ovulation and directs eggs into oviduct

Uterus Also called the womb Place where the fetus grows

Cervix Neck of uterus Separates the uterus from the vagina Serves as a passageway from sperm to travel from the vagina to the uterus and also seals the uterus during pregnancy

Vagina Connects the vulva to the cervix Receives the male penis and sperm at breeding Serves as a passageway fro urine to be expelled

Vulva External opening to female reproductive and urinary systems

Livestock and Poultry Male Reproductive Parts

Scrotum Sheath Saclike part outside livestock Holds and protects the testicles Sheath Protects the penis from injury

Testes or testicles Two oval structures inside the scrotum in livestock and inside the body cavity of poultry on each side of the backbone Produce sperm and male sex hormones

Epididymis Long coiled tube connected to each testicle Stores sperm while they mature

Vas deferens Seminal vesicles Prostrate gland Cowper’s gland Tube that connect the epididymis to urethra Seminal vesicles Open to urethra Prostrate gland Near the urethra and bladder Cowper’s gland Near urethra

Penis Covered by the sheath Part that penetrates the female at breeding Deposits semen in female livestock Papilla serve this function in poultry

Accessory male reproductive glands Produce fluids to protect and carry the sperm Cowper’s gland Prostrate gland Seminal vesicles

Testicles are removed by castration to keep males from breeding

Papilla is the organ in male poultry’s cloaca wall that puts the sperm in the hen’s reproductive tract.

Poultry Reproductive System The major difference between livestock and poultry reproductive systems is that the embryo of livestock develops inside the female’s body and the poultry embryo develops outside the body.

Chickens (domestic birds) have only the left ovary and oviduct functional at maturity. This is what produces the eggs The right ovary and oviduct do not function

The ovary produces the ova (eggs) and hormones

In poultry eggs the yolk is the ovum.

The poultry oviduct has five parts Vagina Uterus Isthmus Magnum Infundidbulum

The vent is the outside opening to the poultry reproductive tract.

The uterus and vagina are part of the egg production and egg laying process.

Functions of Poultry Reproductive System Ovary Produces ova or yolks and hormones Infundidbulum The place where fertilization takes place Magnum Secretes the thick egg white or albumen Isthmus Adds the two shell membrane

Uterus Secretes the thin white, the shell, and the shell pigment Vagina Holds the egg until it is laid Oviduct Serves several functions because it is made up of several parts Infundidbulum Magnum Isthmus

Incubation time for chickens is 21 days Cloaca Egg passes through Semen is deposited here during breeding Vent Place where eggs pass out of the hen’s body The outside opening Egg Function is reproduction but is eaten as food by humans and wild animals Incubation time for chickens is 21 days Incubation time for ducks and turkeys is 28 days

Types of Breeding Systems Purebred Breeding Mating a registered purebred male and female of the same breed Angus X Angus

Crossbreeding Mating a male and female of different breeds Angus X Hereford= Crossbred Calf Crossbred X Purebred= Crossbred Crossbred X Crossbred= Crossbred

Inbreeding Mating closely related animals Brother X Sister Son X Mother Father X Daughter

Linebreeding Breeding more distant relatives than inbreeding Can be traced back to one common ancestor such as a grandparent Cousin X Cousin

Grading up Mating a purebred male (sire) to grade or unregistered or crossbred female (dam) to improve the herd Yorkshire boar X Yorkshire/Hampshire sow

Hybrid vigor The superior traits that come from crossbreeding causing the offspring to have traits better than either parent