Reproductive Medicine and Theriogenology Flashcards

Cats are classified as induced ovulators, meaning that:

Answer: Ovulation requires the mechanical stimulus of coitus or exogenous GnRH to trigger the LH surge

In cats, vaginal and cervical stimulation during coitus (or GnRH administration) triggers the hypothalamic-pituitary LH surge required for ovulation; estrus can persist without mating.

In cryptorchid horses, the retained abdominal testicle:

Answer: Produces testosterone normally but fails to produce fertile sperm due to elevated intra-abdominal temperature

The retained testicle in cryptorchid stallions maintains normal endocrine (testosterone) function but cannot produce viable sperm because spermatogenesis requires scrotal temperatures approximately 2–4°C below core body temperature.

Vaginal cytology in dogs is used primarily to:

Answer: Determine the stage of the estrous cycle by examining the ratio of superficial, intermediate, and parabasal cells

Canine vaginal cytology identifies the estrous cycle stage through the proportion of cell types: parabasal cells dominate anestrus, intermediate cells dominate proestrus, and superficial (cornified) cells predominate during estrus.

In cattle, fertilization normally occurs at the:

Answer: Ampullary-isthmic junction of the uterine tube (oviduct)

In cattle and most mammals, fertilization takes place at the ampullary-isthmic junction, where the sperm population that has undergone capacitation meets the ovulated oocyte.

Which of the following best describes relaxin's role in canine reproduction?

Answer: It is produced by the placenta and serves as a detectable serum marker of true pregnancy from approximately day 25–30

Canine relaxin is produced exclusively by the chorioallantoic placenta and is detectable in blood by approximately days 25–30, distinguishing true pregnancy from pseudopregnancy in bitches.

In cattle, retained fetal membranes (RFM) are defined as failure to expel the placenta within:

Answer: 24 hours post-partum

RFM in cattle is defined as retention of fetal membranes beyond 24 hours post-calving, after which the risk of metritis and long-term reproductive failure increases substantially.

For non-invasive reproductive monitoring in exotic and zoo animals, which hormones are most commonly measured in fecal samples?

Answer: Estrogen metabolites (estrone conjugates) and progestagen metabolites, which reflect circulating hormone levels

Fecal estrogen metabolites and progestagen metabolites are excreted via the bile and gastrointestinal tract, providing a non-invasive window into reproductive cycles without requiring blood collection from stress-sensitive species.