WF-R ANIMAL SCIENCE 1 Animal Reproduction and Genetics

WF-R ANIMAL SCIENCE 1 Terminology Objective: –Define terminology related to reproductive management and breeding systems including castration, colustrum, estrus, gestation, lactation and parturition.

WF-R ANIMAL SCIENCE 1 Terminology Castration- removing the testicles of male animals to prevent breeding. Colostrum- the first milk produced after a mammal gives birth that contains antibodies needed for immunity. Estrus- the time a female animal is receptive to be bred, also called heat.

WF-R ANIMAL SCIENCE 1 Terminology Estrus Cycle- the length of a female’s cycle from one estrus to the next. Gestation- the time an animal is pregnant. Puberty- age at which animals reach sexual maturity and begin come into heat.

WF-R ANIMAL SCIENCE 1 Terminology Lactation- the period of time that milk is secreted by the mammary glands. Parturition- the act of giving birth by female mammals. Ovulation- the release of the egg cell from the ovary. Fertilization- the union of the sperm and the egg cells.

WF-R ANIMAL SCIENCE 1 Breeding Systems Objective –Discuss crossbreeding, grading-up, inbreeding, linebreeding, and purebreeding

WF-R ANIMAL SCIENCE 1 Breeding Systems Pure Breeding –Registered male and female animals –Angus X Angus

WF-R ANIMAL SCIENCE 1 Breeding Systems Cross Breeding –Mating a male and female of different breeds –Angus X Charolais = Crossbreed

WF-R ANIMAL SCIENCE 1 Breeding Systems Inbreeding –Mating closely related animals –Brother X Sister –Son X Mother –Father X Daughter

WF-R ANIMAL SCIENCE 1 Breeding Systems Linebreeding –Breeding more distant relatives than inbreeding –Cousin X Cousin

WF-R ANIMAL SCIENCE 1 Breeding Systems Grading-Up –Mating purebred male (sires) to unregistered or crossbred females (dams) –Yorkshire boar X Yorkshire/Hampshire sow –Hybrid Vigor Superior traits from crossbreeding Offspring are better than parents

WF-R ANIMAL SCIENCE 1 The Female Reproductive System Objective: Identify the parts of the female reproductive system of livestock

WF-R ANIMAL SCIENCE 1 Female Tract

WF-R ANIMAL SCIENCE 1 Female Reproductive System Ovary - the ovary is comparable to the male testicle and is the site of gamete production. –A bovine animal has 20,000 potential eggs per ovary, while a human female has 400,000 potential eggs per ovary. –Ova are fully developed at puberty and are not continuously produced as in the male. –All species contain two functional ovaries except for the hen which has only a left functioning ovary.

WF-R ANIMAL SCIENCE 1 Female Reproductive System The ovaries have three major functions: Gamete production Secrete estrogen (hormone) absence of muscle development development of mammary glands development of reproductive systems and external genitalia fat deposition on hips and stomach (source of energy) triggering of heat Form the corpus luteum

WF-R ANIMAL SCIENCE 1 Female Reproductive System Infundibulum - the funnel shaped portion of the fallopian tube near the ovary that catches the ovulated egg. Oviducts- pair of small tubes leading from the ovaries to the horns of the uterus (5 - 6 inches). –Fertilization occurs in the oviduct. –Egg travels from ovary to uterine horn in days.

WF-R ANIMAL SCIENCE 1 Female Reproductive System Uterus - Muscular sac connecting fallopian tubes and cervix 1. Sustains the sperm and aids in its transport 2. Supports embryo and fetus during gestation 3. Expels fetus at parturition

WF-R ANIMAL SCIENCE 1 Female Reproductive System Cervix –Area between the uterus and vagina –Normally closed –Opens at estrus and parturition –(2 -3 inches)

WF-R ANIMAL SCIENCE 1 Female Reproductive System Vagina - the female organ of copulation 1. admits penis 2. receives semen 3. passageway for fetus at parturition Vulva - extended genitalia; opening for both urinary and genital tracts

WF-R ANIMAL SCIENCE 1 Reproductive Functions (Female) Steps in the female reproductive process: 1. Ovulation —Produce gamete (ova or ovum) —Release of egg(s) —Infundibulum pushes the ovum into the fallopian tube

WF-R ANIMAL SCIENCE 1 Reproductive Functions (Female)

WF-R ANIMAL SCIENCE 1 Reproductive Functions (Female) 2.Estrus (heat, estrous period) –Period of time when a female will accept a male in copulation

WF-R ANIMAL SCIENCE 1 Reproductive Functions (Female) 3. Gestation —Fertilization to parturition —Develop embryo in uterus 4. Parturition —Expel fully developed young at birth 5. Lactation —Milk production

WF-R ANIMAL SCIENCE 1 Ovulation Rates 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

WF-R ANIMAL SCIENCE 1 Reproductive Terminology SpeciesAct Offspring Cows Ewes Sows Henshatchingchick Mares Goats

WF-R ANIMAL SCIENCE 1 SpeciesAct Offspring Cowscalvingcalf Eweslambinglamb Sowsfarrowingpig Henshatchingchick Maresfoalingfoal Goatskiddingkid

WF-R ANIMAL SCIENCE 1 Reproductive Functions (Female) Gestation and Lactation Periods: SpeciesGestation PeriodLactation(Milking) Cow days beef days dairy days Ewe days days Sow days days Mare days days Woman 270 days ? years

WF-R ANIMAL SCIENCE 1 Reproductive Functions (Female) Estrous period length by species: Cow hours Ewe hours Sow hours Mare hours Hens & Womennone

WF-R ANIMAL SCIENCE 1 Reproductive Functions of the Female Estrous cycle - time from one heat period (or menstrual cycle) to the next. Length of estrous cycle by species: Cow days Ewe days Sow days Mare days Woman28 days HennoneHow to AI a CowHow to AI a Cow

WF-R ANIMAL SCIENCE 1 Summary SpecieAge Range at Puberty Average Length of Estrus Cycle Average Length of Estrus Average Length of Gestation Cow6-8 months21 days16-18 hours283 days Swine4-7 months21 days3 days114 days Sheep4-8 months22 days30 hours148 days Goat1 st autumn22 days2.5 days151 days

WF-R ANIMAL SCIENCE 1 The Male Reproductive Tract Objective: Identify the parts of the male reproductive system of livestock and poultry

WF-R ANIMAL SCIENCE 1 Male Reproductive Tract

WF-R ANIMAL SCIENCE 1 Male Reproductive Tract Scrotum - external sac that holds testicles outside of the body to keep sperm at 4-5 o F cooler than the body temperature Testicles - the primary male organs of reproduction to produce sperm to secrete testosterone

WF-R ANIMAL SCIENCE 1 Male Reproductive Tract Epididymis - Long coiled tube that is a path for sperm (connected to each testicle) –Provide passageway for sperm out of the seminiferous tubules –Storage for sperm –Place for sperm maturation

WF-R ANIMAL SCIENCE 1 Male Reproductive Tract Vas Deferens - slender tube from epididymis to urethra which moves sperm to the urethra Urethra - long tube from bladder to penis; passageway for urine and sperm out of the body

WF-R ANIMAL SCIENCE 1 Male Reproductive Tract Penis - male organ of copulation which conveys semen and urine out of the body, covered by a sheath

WF-R ANIMAL SCIENCE 1 Male Reproductive Tract Accessory Glands: –Seminal Vesicles Function: Produce a fluid that protects and transports sperm. Description: A gland that opens into urethra. –Prostate Gland Function: Produces a fluid that is mixed with the seminal fluid. Description: Gland near the urethra and bladder.

WF-R ANIMAL SCIENCE 1 Male Reproductive Tract Cowper’s Gland –Function: Produces a fluid that moves down the urethra ahead of the seminal fluid. It cleans and neutralizes the urethra to protect the sperm. –Description: A gland near the urethra.

WF-R ANIMAL SCIENCE 1 Male Reproductive Tract

WF-R ANIMAL SCIENCE 1 Reproduction in Poultry Objective: Specify how the reproductive system for poultry functions

WF-R ANIMAL SCIENCE 1

Reproduction in Poultry Ovary- poultry only have one functioning ovary as compared to livestock animals. –Function: Produces ova and hormones. The yolk of an egg is the ovum. –Description: An attached cluster of yellow, round egg yolks. Infundibulum –Function: The place where fertilization takes place. –Description: Funnel shaped structure located just below the ovary. It is the start of the oviducts.

WF-R ANIMAL SCIENCE 1 Reproduction in Poultry Oviduct- tube like structure that consists of five parts: –Magnum- secretes the thick egg white or albumen. –Isthmus- adds the two shell membranes. –Uterus- secretes the thin white, the shell and the shell pigment. –Vagina- holds the egg until it is laid.

WF-R ANIMAL SCIENCE 1 Reproduction in Poultry Cloaca –Function: Location where the papilla of the male bird deposits semen. Egg also passes through this part. –Description: Located between vent and base of oviduct. Vent –Function: Expel egg, liquid and solid waste. –Description: Outside opening to the poultry reproductive tract.

WF-R ANIMAL SCIENCE 1

Reproduction in Poultry The major difference between mammals and poultry reproductive systems is that the embryo of livestock develops inside the female’s body and the poultry embryo develops outside the body. Papilla is the organ in male poultry’s cloaca wall that puts the sperm in the hen’s reproductive tract Chickens (domestic birds) have only the left ovary and oviduct functional at maturity (produce eggs). The right ovary and oviduct do not function.

WF-R ANIMAL SCIENCE 1 Reproduction in Poultry Egg- function is reproduction, but is eaten as food by humans and wild animals. Domestic chickens lay an egg every hours regardless even if sperm are not present. Commercially sold eggs are not fertilized. Incubation time for chicken eggs is 21 days. Turkeys and ducks eggs incubation is 28 days.

WF-R ANIMAL SCIENCE 1 Animal Reproduction and Genetics Objective: Describe the cell and process involved in cell division including how genes affect the transmission of characteristics

WF-R ANIMAL SCIENCE 1 Parts of a cell Protoplasm- the material or contents inside of a cell.

WF-R ANIMAL SCIENCE 1 Parts of a cell Cell Membrane- a thin layer of protein and fat that surround the cell. Some substances can pass into the cell and the membrane blocks others materials from entering. Cell Membrane

WF-R ANIMAL SCIENCE 1 Parts of a cell Centrosome- small body where the microtubules are made. The centrosome divides during mitosis. Centrosome

WF-R ANIMAL SCIENCE 1 Parts of a cell Nucleus- gives cell ability to grow, digest food and divide. Contains chromosomes and DNA. Nucleus

WF-R ANIMAL SCIENCE 1 Parts of a cell Cytoplasm- a jellylike substance that gives the cell shape and contains components necessary for cell functions. Cytoplasm

WF-R ANIMAL SCIENCE 1 Parts of a cell Golgi body- located near the nucleus and produces the membrane that surrounds the lyosomes. Golgi body

WF-R ANIMAL SCIENCE 1 Parts of a cell Lyosome- round shaped organelles that contain digestive enzymes that allow for digestion of cell nutrients. Lysosome

WF-R ANIMAL SCIENCE 1 Parts of a cell Mitochondrion- rod-shaped organelles that convert the energy stored in glucose into ATP (adenosine triphosphate). Mitochondrion

WF-R ANIMAL SCIENCE 1 Parts of a cell Nuclear membrane- the membrane that surround the nucleus. Nuclear membrane

WF-R ANIMAL SCIENCE 1 Parts of a cell Nucleolus- organelle found inside the nucleus. Produced ribosomal RNA. Nucleolus

WF-R ANIMAL SCIENCE 1 Parts of a cell Endoplasmic Reticulum- transports materials through the cell. Rough ER Smooth ER

WF-R ANIMAL SCIENCE 1 Parts of a cell Vacuole- fluid filled membrane that fills with food and waste products inside the cell. Vacuole

WF-R ANIMAL SCIENCE 1 Parts of a cell Ribosome- site of protein synthesis. Ribosome

WF-R ANIMAL SCIENCE 1 Cell Division Mitosis –Increases total number of cells –Results in animal growth –Chromosomes pairs are duplicated Meiosis –Produces gametes –Only have one-half the chromosomes of normal cells Videos:

WF-R ANIMAL SCIENCE 1 Fertilization When the sperm from a male reaches the egg from a female Two cells join to form a complete cell Pairs of chromosomes are formed again Many different combinations of traits are formed

WF-R ANIMAL SCIENCE 1 Fertilization

WF-R ANIMAL SCIENCE 1 Chromosomes Rod shaped bodies Made of protein Found in the cell nucleus Exist in pairs except for gamete cells The number of chromosome pairs differ for various animals –Cattle 30 –Swine 19 –Horses 32 –Chickens 39 –Humans 23

WF-R ANIMAL SCIENCE 1 Genes Located on chromosomes Thousands found in each animal Control inherited characteristics –Carcass traits –Growth rate –Feed efficiency Two types of inherited traits  Dominant  Recessive

WF-R ANIMAL SCIENCE 1 Genes Dominant gene –Hides the effect of another gene –Polled condition in cattle is dominant –The gene is represented by a capital letter Recessive –Gene that is hidden by another –The gene is represented by a lower case letter

WF-R ANIMAL SCIENCE 1 Genes Example: The dominant gene is written- P The recessive gene is written-p P= Polled p= horned

WF-R ANIMAL SCIENCE 1 Homozygous and Heterozygous Homozygous gene pair –Carries two genes for a trait –Polled cow might carry the gene PP Heterozygous –Carries two different genes that affect a trait –Polled cows might carry a recessive gene with the dominant Pp

WF-R ANIMAL SCIENCE 1 Predicting Genotype Genotype-kind of gene pairs possessed Phenotype- the physical appearance of an animal Punnett squares are used to predict genotypes and phenotypes of animals

WF-R ANIMAL SCIENCE 1 Genotypes Three class genotypes Homozygous Dominant = PP Homozygous Recessive = pp Heterozygous = Pp P = Polled & p = horned Six possible crosses: PP x PP, PP x Pp, PP x pp, Pp x Pp, Pp x pp, pp x pp

WF-R ANIMAL SCIENCE 1 Punnett Square P= Polled p= horned Example: Two polled cattle that are homozygous for the polled trait Genotypic Ratio: 4PP : 0 Phenotypic Ratio:4 polled animals PP PPP P Polled Dam Polled Sire Polled Dam Polled Sire

WF-R ANIMAL SCIENCE 1 Punnett Square N= Normal size n= Dwarfism Example: Normal size in cattle is dominant to dwarfism Genotypic Ratio: Phenotypic Ratio: NN NNN nNn Normal Dam Sire Carrier Normal Dam Sire Carrier

WF-R ANIMAL SCIENCE 1 Punnett Square N= Normal size n= Dwarfism Example: What if both parents are carriers for a trait or disorder? Genotype: Phenotype: Nn NNNNn n nn Normal Dam Sire Carrier Normal Dam Sire Carrier

WF-R ANIMAL SCIENCE 1 Assignment Complete a Punnett Square for two animals that are heterozygous for two traits: Polled=P Black= B (Alternatives are horned and red) Dam Sire

WF-R ANIMAL SCIENCE 1 Answer A Punnett Square for two animals that are heterozygous for two traits: Polled=P Black= B (Alternatives are horned and red) PBPbpBpb PB PPBBPPBbPpBBPpBb Pb PPBbPPbbPpBbPpbb pB PpBBPpBbppBBppBb pb PpBbPpbbppBbppbb Dam Sire

WF-R ANIMAL SCIENCE 1 Heritability Objective: –Discuss hertability estimates for beef and swine

WF-R ANIMAL SCIENCE 1 Heritability Estimated the likelihood of a trait being passes on from the parent to the offspring –Low heritability slow herd improvement –High heritability faster improvement

WF-R ANIMAL SCIENCE 1 Heritability Swine rates are usually lower than cattle Heritiability for carcass traits are higher than reproductive traits Estimates vary from 0 to 70% Traits with low heritability estimates are improved most through environment, and those traits with high heritability estimates are improved most by selective breeding and environmental improvements.

WF-R ANIMAL SCIENCE 1 Birth weight40% Weaning Weight25-30% Yearling Weight60% Fertility10% Tenderness60%

WF-R ANIMAL SCIENCE 1 Heritability Review Herd improvement –slow for low heritability –faster for high heritability Estimates are higher for: –beef compared to swine –carcass traits compared to repro