Animal Reproduction

Female Vocabulary Ovary- female gonad that produces ova (eggs), and hormones estrogen and progesterone Oviduct-(Fallopian tube) tube that extends from ovary to uterus. Carries ova to uterus. Not attached to ovary. Uterus- hollow organ with thick, muscular walls and mucus lining. Houses developing embryo during pregnancy. Embryo attaches to uterine wall. Sits on top of bladder and below rectum.

Cervix- between uterus and vagina, consists of think ring-like muscles called sphincters. Prevents foreign substances from entering uterus. Normally closed except during estrus. Vagina- extends from cervix to outside the body. Serves as passage for semen into body, and offspring out of the body. Vulva- female external genetalia. External opening to urogenital tract. Why does the cervix prevent foreign substances from entering the uterus?

Estrous Cycle Follicular Phase Proestrus- period when follicles (ova/eggs) grow. Uterine lining develops, animal not sexually receptive yet. Depending on species, could last 3 weeks or 1 day Estrus- short length of time (couple hours to just 1 or 2 days), period of sexual receptivity. Ovulation occurs. Large production of estrogen Ovulation- ovary releases ova/egg into oviduct

Estrous Cycle, cont’d Luteal Phase Metestrous- Estrogen subsides, Corpus Luteum develops. Uterus produces small amounts of hormone Progesterone. Lasts 1-5 days Diestrous- Corpus Luteum produces large quantities of Progesterone (if pregnant). When Corpus Luteum regresses, diestrous ends, proestrous begins again. Lasts up to a number of weeks. Anestrus – period of time when animal does not experience estrous cycle. This could be due to season (in seasonally polyestrous animals), pregnancy, lactation, illness, or age

Estrous Cycles Polyestrous- animals that have more than one estrous cycle per year. Ex: cats, cows, pigs, horses Seasonally Polyestrous- animals that have estrous cycles in a specific time of year Long day breeders (spring): horses, hamsters Short day breeders (fall): sheep, goats, deer Diestrous- animals that have estrous cycles twice a year: Dogs

Monestrous- animals that have only one estrous cycle per year. Ex: bears, foxes, wolves Induced ovulators- animals in which ovum (eggs) are only released after copulation (mating) Ex: cats, rabbits, llamas, ferrets

Gestation Lengths Dog (Bitch)- 63 days Cat (Queen)- 63 days Rabbit (Doe)- 31 days Horse (Mare)- 340 days Cow (Cow)- 285 days Pig (Sow)- 114 days (3 months, 3 weeks, 3 days) Sheep (Ewe)- 147 days Goat (Doe)- 150 days Chicken (Hen)- 21 days

Uterine Bodies Simplex- no uterine horns. Primates (humans) Duplex- Large horns, no uterine body, 2 cervices (cervix). Rodents and lagomorphs (rabbits, hares) Bicornuate- has both uterine horns and uterine body. Pigs, cow, mare, sheep

Sheep Using play-doh, create each of these uterine bodies.

Stages of Prenatal Growth Fertilization- when sperm and egg (ova) unite Attachment- when the embryo attaches itself to the uterus for further development Types of placenta Diffuse- horse, pig Cotyledon- cow, sheep etc. Zonary- dogs, cats, bears, elephants Discoidal- primates, rodents Embryonic Stage- Period when body parts and organs start to form Fetal Stage- Period when body parts and organs mature. Lasts until birth

Bulbourethral Gland

Male Vocabulary Scrotum- external sac that houses and protects testicles. Keeps testicles at temp slightly lower than the body. Testicles- Male sex glands that produce sperm and hormone testosterone Epididymis- Where sperm are store to mature Vas deferens- (ductus deferens)- transports sperm from epididymis to urethra Urethra- tube passing through penis to outside of body, transporting urine and semen.

Accessory Sex Glands- Provide fluids to semen which provide health and nutrition to sperm Seminal Vesicles, Prostate Gland, Bulbourethral glands Penis- Male sex organ, carries semen and urine out of body. Made of erectile tissue that fills with blood upon stimulation, this causes erection.

AI vs. Natural Cover vs. In-vitro Artificial Insemination- semen is ‘collected’ from the male (sire/stud) and manually depositing into female Pros- can breed more females in a short time, better genetic selection Cons- expensive, requires specialized training, costs time and labor Natural Cover- actual physical mating of a male and female of a species Pros- cheaper, less time required by owner Cons- dangerous to stud, limited to local/cheap studs In-vitro- process in which egg/ova is fertilized outside the uterus (ie test tube/culture dish Pros- can utilize genes of superior female that cannot reproduce (not so much cows Cons- very expensive

Dystocia Definition- difficult birth During birth, when the baby (calf, lamb, foal) presents itself in the wrong position Correct position- front hooves first, then nose, then rest of body.

Twinning- Multiples are very common in sheep, and sometimes occur in cattle. Rare in horses and twin foals don’t always survive. Freemartinism- sexual abnormality in cattle. Causes infertility in a female calf born with a male twin. Female demonstrates male behavior and has non-functioning ovaries Occasionally occurs in pigs, sheep, goats

Genetics Autosomes- chromosomes that determine traits other than gender Sex Chromosomes- 1 pair of chromosomes that determine gender X Chromosome- Female (XX) Y Chromosome- Male (XY) Half of total chromosomes come from father, half come from mother

Phenotype- outwardly displayed trait Genotype- genetic code of a specific trait 2 types of traits: Dominant and Recessive Dominant genes will ALWAYS be displayed Recessive genes will only be displayed if there is no dominant gene present Homozygous Dominant- BB Homozygous Recessive- bb- recessive is shown Heterozygous- Bb – Dominant is shown

B BB Punnett Squares Parent 1’s Chromosomes of specific trait   B BB Parent 2’s Chromosomes of specific trait

100 % of offspring will show dominant trait Homozygous Dominant   B BB 100 % of offspring will show dominant trait

100% of offspring will show recessive trait Homozygous Recessive   b bb 100% of offspring will show recessive trait

Heterozygous B b BB Bb bb   B b BB Bb bb 25% of offspring will beHomozygous Dominant (BB) 25% of offspring will be Homozygous Recessive (bb) 50% of offspring will be Heterozygous (Bb) 75% will show Dominant trait 25% will show Recessive Trait

On your own….