Animal Reproduction and Genetics
COMPETENCY: 014.00
Discuss reproduction management used in the animal science industry.
OBJECTIVE: 014.01
Define terminology related to reproductive management and breeding systems including castration, colustrum, estrus, gestation, lactation, and parturition
Terminology
•
Castration
– __________________________________________________
•
Colustrum
– __________________________________________________
•
Gestation
– __________________________________________________
•
Estrus
– __________________________________________________
•
____________________________
– Period of time that milk is secreted by the mammary glands
•
Parturition
– __________________________________________________
OBJECTIVE: 014.02
Discuss crossbreeding, grading up, inbreeding, linebreeding, and purebred breeding
Breeding Systems
•
Pure Breeding
– ________________________________________________
– ________________________________________________
•
Cross Breeding
– ________________________________________________
– ________________________________________________
•
Inbreeding
– ________________________________________________
– ________________________________________________
– ________________________________________________

– ________________________________________________
•
Linebreeding
– Breeding more distant relatives than inbreeding
– ________________________________________________
•
Grading-Up
– Mating purebred ___________________ to unregistered or corssbred _________________________
– ________________________________________________
– Hybrid Vigor
• ______________________________________________
• ______________________________________________
COMPETENCY: 015.00
Analyze how the female reproductive system of livestock functions.
OBJECTIVE: 015.01
Identify the parts of the female reproductive system of livestock.
Female Reproductive System
Ovary - the ovary is comparable to the male testicle and is the site of
___________________ production.
– A bovine animal has __________________ potential eggs per ovary, while a human female has __________________ potential eggs per ovary.
Ova are fully developed at ____________________ and are not –
– continuously produced as in the male.
All species contain two functional ovaries except for the hen which has only a _________________ functioning ovary.
The ovaries have three major functions:
• ____________________ production
• Secrete _______________________________ (hormone) o absence of muscle development o development of mammary glands o development of reproductive systems and external genitalia o fat deposition on hips and stomach (source of energy) o ______________________________________________
• Form the ___________________________________________
Infundibulum - the ____________________shaped portion of the fallopian tube near the ovary that ___________________ the ovulated egg.

_______________________________ - pair of small tubes leading from the ovaries to the horns of the uterus (5 - 6 inches).
– ______________________________ occurs in the oviduct.
– Egg travels from ovary to uterine horn in ______________ days
_______________________________ - The anterior, divided end of the uterus in the cow, ewe, and mare. Sow has only 2 horns, no body, woman has no horns, only body.
Uterus - Muscular sac connecting fallopian tubes and cervix
1. Sustains the sperm and aids in its _______________________
2.
__________________________________________________________
________________________________________________
3. Expels fetus at parturition
Cervix
– ____________________________________________________
–
–
Normally closed
Opens at estrus and parturition
(2 -3 inches) –
Vagina -
_____________________________________________________________
___________________________________________________
1. admits penis
2. receives semen (except in __________________)
3. passageway for _________________________ at parturition
Bladder - ________________________________________________
______________________ - extended genitalia; opening for both urinary and genital tracts
Reproductive Functions (Female)
Steps in the female reproductive process:
1. Ovulation
— Produce gamete (ova or ovum)

— ________________________________________________
— Infundibulum pushes the ovum into the fallopian tube
2. Estrus (heat, estrous period)
–Period of time when a female will accept a male in copulation
–The female must stand (standing heat) to be mounted before the reproductive process can begin
3. Gestation
— ________________________________________________
— ________________________________________________
4. _________________________
— Expel fully developed young at birth
5. Lactation
— _________________________________________________

Ovulation Rates by Species
Cow- __________________________________________
Ewe- __________________________________________
Sow- __________________________________________
Mare-__________________________________________
Hen- Approx. ______________________ eggs per month
Gestation and Lactation Periods
Species Gestation Period Lactation(Milking)
Cow
Ewe
Sow
Mare
Woman
275 - 285 days beef 180 - 270 days dairy 305 - 365 days
115 - 142 days 60 - 90 - 120 days
112 - 115 days 21 - 42 days
330 - 345 days 90 - 150 days
270 days ? years
Estrous period length by species:
Cow ________________ hours
24 - 36 hours Ewe
Sow
Mare
48 - 72 hours
90 - 170 hours
Hens & Women ________________
Estrous cycle - time from one ________________ (or menstrual cycle) to the next.
Length of estrous cycle by species:
Cow
Ewe
Sow
Mare
Hen
19 - 21 days
16 - 17 days
19 - 21 days
21 - 24 days
Woman 28 days none
The Male Reproductive Tract

_______________________ - external sac that holds testicles outside of the body to keep sperm at _______________ cooler than the body temperature
Testicles - the primary male organs of reproduction
•
•
_______________________________________________
_______________________________________________
Epididymis - _________________________ that is a path for sperm
–
–
–
–
Provide passageway for sperm out of the seminiferous tubules
__________________________________________________
Fluid secretion to nourish sperm
__________________________________________________
___________________________ - slender tube from epididymis to urethra which moves sperm to the urethra at ejaculation
Urethra - long tube from _________________________; passageway for urine and sperm out of the body
____________________________ - male organ of copulation which conveys semen and urine out of the body
Penis retractor muscle - allows extension and retraction of the penis; sigmoid flexure extends in copulation

Accessory Glands:
•Seminal vesicles- add fructose and citric acid to nourish the sperm
•Prostate Gland - located at the neck of the bladder
–
–
–
________________________ prior to and during ejaculation
_________________________________________________ provides the medium for sperm transport
• Cowper’s gland
•Also called the _________________________________ gland
•Paired organs
•Cleans the urethra prior to semen passage
Reproduction in Poultry
COMPETENCY: 017.00
Examine animal science reproduction in poultry.
OBJECTIVE: 017.01
Describe the reproductive system of egg-laying species such as poultry.
The poultry oviduct has five parts:
1) Vagina
– _____________________________________________
2) Uterus
– _____________________________________________
3) Isthmus
– _____________________________________________
4) Magnum
– _____________________________________________
5) Infundibulum
– _____________________________________________
Reproduction in Poultry
Major difference: o Embryo of livestock develop inside female’s body while the embryo of poultry develops inside the egg. o Poultry only have the ___________ ovary and oviduct when mature o Chicken Incubation
– __________________ days the

Animal Reproduction and Genetics
COMPETENCY: 018.00
Recognize the importance of genetics in animal science.
OBJECTIVE: 018.01
Describe the cell and processes involved in cell division including how genes affect the transmission of characteristics.
The body is made up of _____________________ of tiny cells
•
Most of the cell is made up of protoplasm
•
Cell parts:
 Nucleus
 Cytoplasm
 Cell membrane
Cell Division
•
Mitosis
– __________________________________________
– __________________________________________
– __________________________________________
•
Meiosis
– __________________________________________
– Only have one-half the chromosomes of normal cells
Fertilization
•
When the sperm from a male reaches the egg from a female
•
Two cells join to form a complete cell
•
Pairs of _________________________ are formed again
•
Many different combinations of traits are formed
Chromosomes
• _________________________________________________
• _________________________________________________

• Found in the cell nucleus
• _________________________________________________
The number of chromosome pairs differ for various animals
– Cattle _______
– Swine _______
– Horses _______
– Chickens _______
– Humans _______
Genes
• Located on __________________________________
• Thousands found in each animal
• Control inherited characteristics
– Carcass traits
– Growth rate
– Feed efficiency
• Two types of inherited traits
 ___________________________
 ___________________________
• Dominant gene
– __________________________________________________
– __________________________________________________
– __________________________________________________
• Recessive
– __________________________________________________
– __________________________________________________
Example:
The dominant gene is written- P
The recessive gene is written-p
P= Polled p= horned
Homozygous and Heterozygous
•
___________________________ gene pair
– Carries two genes for a trait
– Polled cow might carry the gene PP

•
___________________________
– Carries two different genes that affect a trait
– Polled cows might carry a recessive gene with the dominant Pp
Predicting Genotype
•
Genotype-___________________________________________
•
Phenotype- the ___________________ appearance of an animal
•
___________________________ are used to predict genotypes and phenotypes of animals
Example:
Two polled cattle that are homozygous for the polled trait
P= Polled p= horned

Heritability
OBJECTIVE: 018.02
Discuss heritability estimates for beef cattle and swine.
Heritability-
________________________________________________________
________________________________________________________
________________________________________________________
____________________________________
– Low heritability
•___________________ herd improvement
Heritability
– High heritability
•___________________ improvement
• Swine rates are usually __________________ than cattle
• Heritiability for carcass traits are _________________ than reproductive traits
• Estimates vary from __________________%
Heritability Review
• Herd improvement
– ____________________________________________
– ____________________________________________
• Estimates are higher for:
– ____________________________________________
– ____________________________________________