Animal Reproduction and Genetics WFRANIMALSCIENCE 11 Terminology Objective

Animal Reproduction and Genetics WF-RANIMALSCIENCE 11

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-RANIMALSCIENCE 11

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 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 3 - 4 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 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 Species Cows Ewes Sows Hens Mares Goats WF-R ANIMAL SCIENCE 1 Act Offspring hatching chick

Species Cows Ewes Sows Hens Mares Goats WF-R ANIMAL SCIENCE 1 Act calving lambing farrowing hatching foaling kidding Offspring calf lamb pig chick foal kid

Reproductive Functions (Female) Gestation and Lactation Periods: Species Cow Gestation Period 275 - 285 days Lactation(Milking) beef 180 - 270 days dairy 305 - 365 days Ewe 115 - 142 days 60 - 90 - 120 days Sow 112 - 115 days 21 - 42 days Mare 330 - 345 days 90 - 150 days Woman 270 days ? years WF-R ANIMAL SCIENCE 1

Reproductive Functions (Female) Estrous period length by species: Cow 12 - 18 hours Ewe 24 - 36 hours Sow 48 - 72 hours Mare 90 - 170 hours Hens & Women none 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 19 - 21 days Ewe 16 - 17 days Sow 19 - 21 days Mare 21 - 24 days Woman 28 days Hen none How to AI a Cow WF-R ANIMAL SCIENCE 1

Summary Specie Age Range Average at Puberty Length of Estrus Cycle Cow 6 -8 months 21 days Average Length of Estrus Average Length of Gestation 16 -18 hours 283 days Swine 4 -7 months 21 days 3 days 114 days Sheep 4 -8 months 22 days 30 hours 148 days Goat 1 st autumn 22 days 2. 5 days 151 days WF-R ANIMAL SCIENCE 1

The Male Reproductive Tract Objective: Identify the parts of the male reproductive system of livestock and poultry WF-RANIMALSCIENCE 11

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-RANIMALSCIENCE 11

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

WF-R ANIMAL SCIENCE 1

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 24 -28 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-RANIMALSCIENCE 11

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. WF-R ANIMAL SCIENCE 1 Cell Membrane

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

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

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

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. WF-R ANIMAL SCIENCE 1 Lysosome

Parts of a cell • Mitochondrion- rodshaped 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 • Nucleolusorganelle found inside the nucleus. Produced ribosomal RNA. WF-R ANIMAL SCIENCE 1 Nucleolus

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

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: http: //www. youtube. com/watch? v=C 6 hn 3 s. A 0 ip 0 http: //www. youtube. com/watch? v=-DLGfd-Wpr 4 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 WF-R ANIMAL SCIENCE 1 • The number of chromosome pairs differ for various animals – – – Cattle 30 Swine 19 Horses 32 Chickens 39 Humans 23

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

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

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

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

Answer Sire A Punnett Square Dam for two animals PB Pb p. B pb that are heterozygous for PB PPBb Pp. BB Pp. Bb two traits: Pb PPBb PPbb Pp. Bb Ppbb • Polled=P p. B Pp. Bb pp. BB pp. Bb • Black= B pb Pp. Bb Ppbb pp. Bb ppbb (Alternatives are horned and red) 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 weight 40% Weaning Weight 25 -30% Yearling Weight 60% Fertility 10% Tenderness 60% 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 WF-R ANIMAL SCIENCE 1