AAVSB Reproductive Medicine and Theriogenology

Question 1

In cattle, which hormone is primarily responsible for causing luteolysis at the end of the estrous cycle?

Accepted Answer

Prostaglandin F2α (PGF2α)

Answer

Prostaglandin F2α released from the endometrium causes regression of the corpus luteum, ending the luteal phase of the estrous cycle in cattle.

Question 2

What is the average gestation length in horses?

Accepted Answer

335 days

Answer

The average equine gestation length is approximately 335–340 days, though it can range from 320 to 370 days depending on season and breed.

Question 3

Which of the following species is classified as an induced ovulator?

Accepted Answer

Cat

Answer

Cats are induced ovulators, meaning ovulation is triggered by the mechanical stimulus of copulation rather than occurring spontaneously.

Question 4

During early pregnancy in cattle, the corpus luteum is maintained primarily by which substance secreted by the embryo?

Accepted Answer

Bovine trophoblast protein-1 (bTP-1)

Answer

Bovine trophoblast protein-1 (bTP-1), also called bovine interferon-tau, is secreted by the conceptus to prevent luteolysis and maintain the corpus luteum during maternal recognition of pregnancy.

Question 5

In the bitch, which phase of the estrous cycle is typically the longest and is characterized by uterine quiescence?

Accepted Answer

Anestrus

Answer

Anestrus is the longest phase in the bitch's reproductive cycle, lasting approximately 4–5 months and representing a period of reproductive inactivity between cycles.

AAVSB - American Association of Veterinary State Boards Practice Test

AAVSB - American Association of Veterinary State Boards Practice Test

AAVSB Reproductive Medicine and Theriogenology