Reproduction in Female Domestic Animals

Location GnRH

Produced in the hypothalamus.

Location LH

Produced in the anterior pituitary.

Location FSH

Produced in the anterior pituitary.

Location Progesterone

Produced in the corpus luteum.

Location Inhibin

Produced in granulosa cells.

Location Activin

Produced in granulosa cells.

Location Estradiol

Produced in granulosa cells.

Location Prostaglandins

Produced in the uterine endometrium.

Function Dopamine

Inhibits production of prolactin.

Function Oxytocin

Stimulates smooth muscle contractions of the uterus and milk letdown.

Function Prolactin

Causes mammary growth and milk production, inhibits dopamine.

Function FSH

Stimulates follicular growth, estradiol production by granulosa cells and induces granulosa cells to produce LH receptors.

Function LH

Follicle maturation and ovulation, progesterone secretion and CL maintenance, negative feedback on progesterone.

Function Progesterone

Maintenance of pregnancy.

Function Inhibin

Suppresses FSH.

Function Activin

Stimulates FSH.

Function TRH

Stimulates prolactin synthesis.

Function Estradiol

Negative feedback on FSH.

Function Kisspeptin

Induces GnRH release.

Function GnRH

Induces FSH/LH secretion.

Ferguson reflex

Pressure in the birth canal or on the cervix stimulates release of oxytocin to further stimulate contractions.

Follicular phase

Rising estrogen, intensifying LH pulses, LH surge, ovulation.

Luteal phase

Progesterone is higher than estrogen, inhibition of LH, no heat.

Primordial follicle

Single layer of flat granulosa cells.

Primary follicle

Single layer of cuboidal granulosa cells.

Secondary follicle

Multiple layers of cuboidal granulosa cells.

Tertiary (antral) follicle

Presence of a fluid filled antrum, multiple layers of granulosa, theca cells, has FSH and LH receptors.

Theca cells function

Convert cholesterol into androgens.

Granulosa cells function

Convert androgens into estrogens (FSH).

What is a COC

Cumulus oocyte complex, oocyte surrounded by cumulus cells with zonal projections.

Describe the hormonal process of ovulation

LH surge stimulates relaxin and prostaglandins from the granulosa, connective tissue of the follicle weakens and leads to rupture.

Induced ovulation species

Cats, camelids, ferrets, rabbits.

Progesterone in dogs

Progesterone rises before ovulation.

CL regression hormone. What species do not use this hormone?

Prostaglandins; dogs/cats do not use this hormone.

Unilateral ovarian development species

Most avian.

Can you spay birds? Reptiles/chelonians?

No, but yes for reptiles/chelonian.

what is a Seasonal breeder? what causes changes in seasonal cyclicity?

Only breed during certain times of the year; changes in seasonal cyclicity caused by melatonin.

Determinate layer

Fail to lay additional eggs in the case of egg loss (chelonians, reptiles, budgies, parakeets, most avians; NOT CHICKENS).

What species do we do Ovariectomy and ovariohysterectomy? Advantages? Disadvantages?

Performed on large animals and small animals respectively; advantages include permanence and disease prevention, disadvantages include weight gain, incontinence, reduced estrogen.

how does Ovaban (megestrol acetate) work

Suppresses estrus, mammary development, weight gain, adrenal suppression in dogs.

what does Depo-Provera (medroxyprogesterone acetate) do?

Causes weight gain, adrenal suppression, mammary neoplasia, uterine disease (CEH/cystic endometrial hyperplasia and pyometra) in dogs.

what does Regu-Mate (altrenogest) do?

Blocks secretion of LH from anterior pituitary in horses.

Is Depo-Provera (medroxyprogesterone acetate) recomended in horses

Not effective/recommended.

Anti-progestins (e.g., RU-486) function

Binds the progesterone receptor and prevents action of natural progesterone (not often used in animals).

How do Androgens work?

Inhibits secretion of gonadotropins (LH/FSH) through negative feedback, decreases follicular development and inhibits ovulation.

What is Mibolerone? What are its functions and side effects?

Type of androgen contraceptive; decreases incidence of CEH/pyometra and mammary gland neoplasia in comparison to progestins; side effects include clitoral hypertrophy, discharge, increased aggression.

How do GnRH agonists work?

Have a higher affinity than natural GnRH, down regulates the anterior pituitary with large doses to reduce FSH and LH to prevent follicular development and ovulation.

how do GnRH antagonists work?

Bind to GnRH receptor, biologically inactive, rapid onset, short duration, prevents synthesis/secretion of FSH/LH to inhibit ovulation.

GnRH toxins

Bind to GnRH receptor and kill the cell, decreases FSH/LH.

how does the GnRH vaccine work?

Bound to a larger molecule; anti-GnRH antibodies bind circulating GnRH and prevent it from acting upon its receptor, thus preventing LH/FSH production; antibodies must wane before cyclicity returns; works in males and females.

how does the Zona pellucida vaccine work?

Antibodies against the ZP proteins block the sperm binding site to inhibit fertilization; does not influence ovulation or estrus; immune mediated pathology may occur.

How can you Induce ovulation

GnRH or GnRH agonists stimulate anterior pituitary release of LH to induce ovulation; LH and hCG also act like LH (requires ovarian stimulation for ovulation).

What is Superovulation

Causes ovulation of multiple follicles.

Hormones from dominant follicle

Inhibin and estradiol cause only one follicle to ovulate.

How to Induce superovulation

Administer exogenous FSH or eCG or prevent the action of inhibin through immunoneutralization to allow for the action of endogenous FSH.

What is one method of Synchronize estrus

Administer progesterone for 10-14 days to suppress LH (act as a fake CL); may also administer estradiol to suppress FSH; PGF would be administered at the end of treatment.

Cystic ovaries pathologies

Mostly in dairy cows with a mis-timed LH surge or insufficient estrogen production by the follicle; includes failure to ovulate, partial luteinization, persistent estrus, masculinized, persistent estrus/anestrus, elevated tail head, cystic endometrial hyperplasia, vulva enlargement.

Short cycling indication

Uterine infection or endometritis causing persistent release of PGF and CL lysis.

Causes of pseudopregnancy

Inadequate PGF release, embryonic loss after maternal recognition of pregnancy, severe uterine pathology preventing the release of PGF.

Acute infection effect on PGF

Causes PGF release.

Chronic infection effect on PGF

Inhibits PGF release.

Effect of Fescue ingestion in cows

High dopamine, low prolactin, no milk production.

Phytoestrogens ingestion in cows/ewes can cause what

Causes CEH.

Can you tell systemically if a large animal has a uterine infection? Small animals?

Systemically undetectable in large animals, but detectable in small animals.

Pyometra stage in dogs

Occurs in diestrus.

What hormone is stimulated by high frequency pulses of GnRH?

LH

What hormone is stimulated by low frequency pulses of GnRH?

FSH

What hormone(s) are associated with proestrus

declining progesterone, increasing estradiol

What hormone(s) are associated with estrus

high estrogen

What hormone(s) are associated with metestrus

declining estrogen, increasing progesterone

What hormone(s) are associated with diestrus

high progesterone

What hormone(s) are associated with anestrus

low hormonal action

Is it a good idea to give a bird nesting materials or alter the light cycle?

Yes, it increases folliculogenesis