Theriogenology and Veterinary Reproduction Flashcards

In the bitch, serum progesterone concentrations above 5 ng/mL typically indicate which reproductive event?

Answer: Ovulation has occurred

Progesterone rises above 5 ng/mL after ovulation in the bitch, confirming that ovulation has already taken place.

Which stage of the canine estrous cycle is characterized by vaginal cornification >80% and a marked decrease in neutrophils on cytology?

Answer: Estrus

During estrus, vaginal cytology shows >80% cornified squamous cells and absence of neutrophils, reflecting peak estrogen influence.

In cattle, the corpus luteum (CL) can be lysed using exogenous prostaglandin F2α (PGF2α) between which days of the estrous cycle?

Answer: Days 5–16

PGF2α is effective at lysing the CL only from approximately days 5–16 of the bovine estrous cycle when the CL is mature and responsive.

What is the average gestation length of the mare?

Answer: 335–345 days

The average gestation length in mares is approximately 335–345 days, with normal ranges from 320 to 360 days.

Which feline reproductive characteristic distinguishes cats from dogs in terms of ovulation?

Answer: Cats require mating or cervical stimulation to ovulate (induced ovulation)

Cats are induced ovulators, requiring coital or mechanical cervical stimulation to trigger the LH surge and subsequent ovulation.

A cow presents with a soft, fluid-filled uterus and bilateral enlarged uterine horns at 4 weeks post-calving. The most likely diagnosis is:

Answer: Pyometra

Bovine pyometra post-calving presents as a distended uterus filled with purulent fluid, often associated with a retained CL and bacterial infection.

In equine reproduction, the hormone primarily responsible for maternal recognition of pregnancy and CL maintenance is:

Answer: Equine chorionic gonadotropin (eCG)

eCG (formerly PMSG), produced by endometrial cups from days 40–150, stimulates formation of accessory CLs that maintain progesterone levels during early equine pregnancy.