Animal Reproduction and Genetics
Animal Reproduction and Genetics
8.00: Understand animal reproduction
Terminology
•Castration
–______
•Colustrum
–______
•Gestation
–______
•Estrus
–______
•______
–Period of time that milk is secreted by the mammary glands
•Parturition
–______
•Estrus Cycle
–______
•Puberty
–______
•Ovulation
–______
•Fertilization
–______
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)
- absence of muscle development
- development of mammary glands
- development of reproductive systems and external genitalia
- fat deposition on hips and stomach (source of energy)
- ______
•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
SpeciesGestation PeriodLactation(Milking)
Cow283 daysbeef 180 - 270 days
dairy 305 - 365 days
Ewe148 days60 - 90 - 120 days
Sow114 days21 - 42 days
Mare330 - 345 days90 - 150 days
Estrous period length by species:
Cow______hours
Ewe24 - 36 hours
Sow48 - 72 hours
Mare90 - 170 hours
Hens & Women______
Estrous cycle - time from one ______(or menstrual cycle) to the next.
Length of estrous cycle by species:
Cow 21 days
Ewe22 days
Sow21 days
Mare22 days
Hennone
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
The poultry oviduct has five parts:
1) Vagina
–______
2) Uterus
–______
3) Isthmus
–______
4) Magnum
–______
5) Infundibulum
–______
Reproduction in Poultry
Major difference:
- Embryo of livestock develop inside the female’s body while the embryo of poultry develops inside the egg.
- Poultry only have the ______ovary and oviduct when mature
- Chicken Incubation
–______days
Parturition
Normal Position
- ______
- ______
- Shoulders
- ______
- Hips
- Back legs
- Any other presentation can cause serious problems for the animal
Process
- ______
- ______
- Second water bag emerges and breaks (contains fetus)
- Several hours later, the placenta and other membranes (afterbirth) are expelled
Animal Genetics
The body is made up of ______of tiny cells
•Most of the cell is made up of protoplasm
Cell Parts
Protoplasm
•______
Cell membrane
•______
Nucleus
•______
Cytoplasm
•______
Lyosome
•______
Mitochondrion
•______
Nucleous
•______
Endoplasmic
•______
Nuclear Membrane
•______
Golgi Body
•______
Centrosome
•______
Vacuole
•______
Ribosome
•______
Cell Division
•Mitosis
–______
–______
–______
- Prophase
______
- Metaphase
______
- Anaphase
______
- Telophase
______
•Meiosis
–______
–Only have one-half the chromosomes of normal cells
•Gamete Formation
–______
–The zygote that is created during fertilization has chromosomes from each parent. Chromosomes match up with one another based on the genetic information they carry.
•Production of sperm is called spermatogenesis.
–Male animals begin producing sperm at sexual maturity.
–______
•Production of an ovum is called oogenesis.
–______
–The oocytes divide and form an ovum. The ovum contains cytoplasm and stored food. It provides nourishment for the zygote and embryo.
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
Heritability-
______
–Low heritability
•______herd improvement
–High heritability
•______improvement
Heritability
•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:
–______
–______