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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.
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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.
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
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
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
Punnett Squares Parent 1’s Chromosomes of specific trait Parent 2’s Chromosomes of specific trait
Homozygous Dominant 100 % of offspring will show dominant trait
Homozygous Recessive 100% of offspring will show recessive trait
Heterozygous 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