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Terminology
• Objective:– Define terminology related to reproductive
management and breeding systems including castration, colustrum, estrus, gestation, lactation and parturition.
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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.
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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.
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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.
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Breeding Systems
• Objective– Discuss crossbreeding, grading-up,
inbreeding, linebreeding, and purebreeding
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Breeding Systems
• Pure Breeding– Registered male and female animals– Angus X Angus
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Breeding Systems
• Cross Breeding– Mating a male and female of different breeds– Angus X Charolais = Crossbreed
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Breeding Systems
• Inbreeding– Mating closely related animals– Brother X Sister– Son X Mother– Father X Daughter
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Breeding Systems
• Linebreeding– Breeding more distant relatives than
inbreeding– Cousin X Cousin
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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
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The Female Reproductive System
Objective: Identify the parts of the female reproductive system of livestock
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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.
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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
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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.
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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
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Female Reproductive System
• Cervix – Area between the
uterus and vagina
– Normally closed
– Opens at estrus and parturition
– (2 -3 inches)
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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
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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
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Reproductive Functions (Female)
2. Estrus (heat, estrous period)
– Period of time when a female will accept a male in copulation
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Reproductive Functions (Female)
3. Gestation— Fertilization to parturition— Develop embryo in uterus
4. Parturition— Expel fully developed young at birth
5. Lactation— Milk production
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Ovulation Rates
Ovulation Rates by SpeciesCow- 1 egg per estrusEwe- 1 to 3 eggs per estrusSow- 10 to 20 eggs per estrusMare- 1 egg per estrusHen- Approx. 28 eggs per month
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Reproductive Terminology
Species Act OffspringCowsEwesSowsHens hatching chickMaresGoats
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Species Act OffspringCows calving calfEwes lambing lambSows farrowing pigHens hatching chickMares foaling foalGoats kidding kid
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Reproductive Functions (Female)
Gestation and Lactation Periods:
Species Gestation Period Lactation(Milking)
Cow 275 - 285 days 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
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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
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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
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Summary
Specie Age Range at Puberty
Average Length of
Estrus Cycle
Average Length of
Estrus
Average Length of Gestation
Cow 6-8 months 21 days 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 1st autumn 22 days 2.5 days 151 days
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The Male Reproductive
TractObjective: Identify the parts of the male reproductive system of livestock and poultry
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Male Reproductive Tract
• Scrotum - external sac that holds testicles outside of the body to keep sperm at 4-5oF cooler than the body temperature
• Testicles - the primary male organs of reproduction • to produce sperm • to secrete testosterone
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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
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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
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Male Reproductive Tract
• Penis - male organ of copulation which conveys semen and urine out of the body, covered by a sheath
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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.
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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.
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Reproduction in Poultry
Objective: Specify how the reproductive system for poultry
functions
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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.
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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.
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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.
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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.
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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.
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Animal Reproduction and Genetics
Objective: Describe the cell and process involved in cell division including how genes affect the transmission of characteristics
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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
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Parts of a cell
• Centrosome- small body where the microtubules are made. The centrosome divides during mitosis.
Centrosome
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Parts of a cell
• Nucleus- gives cell ability to grow, digest food and divide. Contains chromosomes and DNA.
Nucleus
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Parts of a cell
• Cytoplasm- a jellylike substance that gives the cell shape and contains components necessary for cell functions.
Cytoplasm
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Parts of a cell
• Golgi body- located near the nucleus and produces the membrane that surrounds the lyosomes.
Golgi body
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Parts of a cell
• Lyosome- round shaped organelles that contain digestive enzymes that allow for digestion of cell nutrients.
Lysosome
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Parts of a cell
• Mitochondrion- rod-shaped organelles that convert the energy stored in glucose into ATP (adenosine triphosphate). Mitochondrion
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Parts of a cell
• Nuclear membrane- the membrane that surround the nucleus.
Nuclear membrane
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Parts of a cell
• Nucleolus- organelle found inside the nucleus. Produced ribosomal RNA. Nucleolus
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Parts of a cell
• Endoplasmic Reticulum- transports materials through the cell.
Rough ER
Smooth ER
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Parts of a cell
• Vacuole- fluid filled membrane that fills with food and waste products inside the cell.
Vacuole
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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
cellsVideos: http://
www.youtube.com/watch?v=C6hn3sA0ip0http://www.youtube.com/watch?v=-DLGfd-Wpr4
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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
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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
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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
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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
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Genes
Example:
The dominant gene is written- P
The recessive gene is written-p
P= Polled
p= horned
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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
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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
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Genotypes
• Three class genotypesHomozygous Dominant = PPHomozygous Recessive = ppHeterozygous = 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
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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
P P
P PP PP
P PP PP
Polled Dam
Pol
led
Sir
e
Polled Dam
Pol
led
Sir
e
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Punnett Square
N= Normal size
n= Dwarfism
Example:• Normal size in cattle is
dominant to dwarfism
Genotypic Ratio:
Phenotypic Ratio:
N N
N NN NN
n Nn Nn
Normal Dam
Sir
e C
arri
er
Normal Dam
Sir
e C
arri
er
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Punnett Square
N= Normal size
n= Dwarfism
Example:• What if both parents are
carriers for a trait or disorder?
Genotype:
Phenotype:
N n
N NN Nn
n Nn nn
Normal Dam
Sir
e C
arri
er
Normal Dam
Sir
e C
arri
er
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Assignment
Complete a Punnett Square for two animals that are heterozygous for two traits:
• Polled=P• Black= B
(Alternatives are horned and red)
Dam
Sir
e
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Answer
A Punnett Square for two animals that are heterozygous for two traits:
• Polled=P• Black= B
(Alternatives are horned and red)
PB Pb pB pb
PB PPBB PPBb PpBB PpBb
Pb PPBb PPbb PpBb Ppbb
pB PpBB PpBb ppBB ppBb
pb PpBb Ppbb ppBb ppbb
Dam
Sir
e
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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
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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.
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Birth weight 40%
Weaning Weight 25-30%
Yearling Weight 60%
Fertility 10%
Tenderness 60%