Reproduction Flashcards
Where are steroid hormones (estrogen, progesterone, testosterone) produced?
Gonads
Adrenal glands
Placenta
HPG Axis
Hypothalamus
Pituitary
Gonadal
What is an ovarian follicle? What hormone does it produce?
- Fluid-filled structure on the ovary containing a soon-to-be ovulated oocyte
- Estrogen
What is a corpus luteum? What hormone does it produce?
- A previous follicle that converts from estrogen production to progesterone production under the influence of LH
- Progesterone
Where are leydig cells located? What hormone do they produce?
- Testes
- Testosterone
Why are Sertoli cells considered “nurse cells”?
Nurture sperm as they develop
What hormone am I?
- Responsible for standing behavior
- Open cervix
- Stimulate moisture in vagina
- Increase thickness of vaginal epithelium
- Increases immune protection of the uterus
Estrogen
What hormone am I?
- Responsible for maintaining pregnancy
- Closes the cervix
- Vagina dry
- Vaginal epithelium thin
- Stimulates glandular development in the uterus to support a pregnancy
Progesterone
What hormone is responsible for inducing ovulation?
Luteinizing hormone (LH)
What does FSH do?
Stimulates follicular development on the ovaries
What does prolactin do?
- Target cells in the mammary gland for lactation
- Maternal behavior
- Support CL in queen and bitch
What hormone is responsible for milk let down and uterine contractions? Where is it produced?
Oxytocin
Posterior pituitary
What enzyme is responsible for the conversion of testosterone to estrogen?
Aromatase - used in breast cancer treatment
What enzyme is responsible for the conversion of testosterone into DHT?
5 alpha reductase
What species are considered short-day breeders?
Goats and sheep
What species are considered long-day breeders?
Cat, horse, ferret
Name the phases of the estrous cycle
Proestrus
Estrus
Metestrus
Diestrus
Anestrus
(Not all females exhibit each phase)
During proestrus, what structure is undergoing regression?
CL from previous cycle
P4 levels start to fall (<1ng/ml)
How long is the cow cycle?
21 days
How long is a cow in estrus?
<24 hours
What is different about ovulation in cows?
Ovulation occurs ~28 hours AFTER estrus
What two phases of the estrous cycle do mares go through?
Estrus and diestrus
+ Anestrus during short days (winter months)
How long is the equine cycle? How many days do they spend in estrous?
21 days
3-9 days
How long is the estrous cycle in the ewe? Does? What kind of breeders are they??
Ewe - 17d
Does - 21d
Short day
Cycle length in sow? How many days in estrus?
21 days
1-3 days
What is special about the hormone profile of dogs during estrus?
Rising progesterone, declining estrogen
How long is proestrus in the bitch? What are clinical signs?
9 days
High estrogen, low progesterone
Vulvar swelling
Serosanguinous vaginal discharge
What is required for ovulation to occur in the queen?
Breeding or induction
“Induced ovulators”
A cat goes through estrus but is NOT bred…when do you expect her next estrus to begin? What is this phase called?
8-10 days; interestrus
A cat is bred during estrus, but does not become pregnant. What happens?
Pseudopregnancy
40 days
A cat is bred and becomes pregnant. How long are they pregnant for?
~60d
How frequently do new follicular waves occur?
Every 8-12 days
Even through periods of anestrus and pregnancy
What must occur in order for a follicle to progress into a dominant follicle?
Luteolysis of CL from previous cycle
How long is metestrus? What structure is present?
5 days
Corpus hemorrhagicum (site of ovulation)
How long is the sow cycle? How many follicular waves do they have?
21 days
1 follicular wave
Cytologically, how can you determine the presence of estrogen?
Cornified stratified squamous epithelium
Describe the cytologically appearance of proestrus
Cornified epithelial cells
RBCs
WBCs
Debris
A bitch in estrus will have >____% superficial epithelial cells
90
What kind of cells are present on vaginal cytology in diestrus?
Parabasilar cells (fried eggs)
Neutrophils! - clean up crew after cervix has been open
Interestrus interval of the bitch
4 mo - 12 mo
Why can’t prostaglandin be used to lyse the CL prior to 5 days post-ovulation?
PGF2a receptors aren’t present until 5 days after ovulation
A mare is accidentally bred by a stallion. O doesn’t want this mare pregnant. What do you do?
Wait 14 days and give lutalyse.
9 days to account for estrus then 5 days for receptors to form
How is ovulation induced in horses?
want a 35mm follicle
- LH analog = hCG
- GnRH analog = Deslorelin
What medications can be used to suppress estrus?
- Progesterone
Which species are luteal independent?
Cow, ewe, mare
Which synchronization program is used in dairy cows? Beef?
OV-Synch = Dairy
Co-Synch = Beef
Describe OV-synch
Day 0: GnRH - recruit new wave
Day 7: PGF2a - lyse CL
Day 9: GnRH - ovulation
Describe CO-synch
Day 1: GnRH - new follicular wave
Day 7: PGF2a - lyse CL
66 hours later: GnRH and AI
Passing spermiogram requirements for bulls/bucks/rams
> 70% morphologically
30% progressively motile
When can the membrane slip be felt in bovine palpation?
35d
When is the amniotic vesicle palpated in a cow?
32-35d
When can a bovine fetus be palpated?
65 days
When are placentomes palpable in bovine?
80d - eraser
90d - dime
120d - quarter
150d - half dollar
When can pregnancy be determined in the mare? What is the preferred method?
14 days; ultrasound
When is the breeding season of horses?
April thru October
Estrus behavior of a mare
Urinating, winking, tail lifting, standing
Breeding options in mare
Every other day beginning on the second day of estrus until mare goes out or heat OR within 24-48 hours prior to ovulation (using ultrasound)
How long is diestrus in the horse?
14-16 days
Side effects associated with PGF2a administration in the mare
Mare CL more sensitive than cows (lower dose)
SE: sweating, abdominal cramps, increased GI motility/colic, increased HR, muscle weakness and balance problems
SE last up to 60 minutes
How to induce ovulation in the mare?
Increase light exposure (16 hours light/day)
When does foal heat occur?
First ovulation occurs 9-10 days after foaling
What is the most common tumor of the equine ovary?
- Granulosa (Theca) Cell Tumor
- Increased testosterone
- Behavioral changes: aggression, stallion like behavior, markedly prolonged estrus, anestrus
- Treatment: ovariectomy
How is GCT/GTCT diagnosed?
Increased AMH, increased Inhibin
U/S
Rectal palpation
Treatment for persistent CL in mare?
Prostaglandins - lyse CL that is continuing progesterone production
What are endometrial cups?
Secrete eCG
“Additional CL”
Take 2-3 months to regress…anestrus until then
T/F: Rectovaginal tears should be repaired the day they occur, if possible.
False - repair after 6 weeks, allowing granulation tissue to form
Cause of contagious equine metritis?
- Taylorella equigenitalis
- CS: copious grey vulvar discharge, asymptomatic
- REPORTABLE
Causative agent of dourine
Trypanasoma equiperidum
“Silver dollar plaques on the ribs”
What is feline mammary fibroepithelial hyperplasia?
Mammary hypertrophy
Common in young, intact female cats
Treatment: OHE
What hormone is responsible for CEH?
Cystic Endometrial Hyperplasia
Progesterone!
What is the most important potential consequence of CEH?
Pyometra
