DVM Reproductive Medicine and Theriogenology

Question 1

In cattle, what is the average length of the estrous cycle?

Accepted Answer

21 days

Answer

14 days

Answer

28 days

Answer

35 days

Question 2

Which hormone is primarily responsible for luteolysis in most domestic species?

Accepted Answer

Prostaglandin F2α (PGF2α)

Answer

Progesterone

Answer

Luteinizing hormone (LH)

Answer

Follicle-stimulating hormone (FSH)

Question 3

The 'freemartin' condition in cattle occurs when:

Accepted Answer

A heifer born twin to a bull shares placental circulation, allowing masculinizing hormones to affect her reproductive tract

Answer

A cow develops an abnormally prolonged estrous cycle

Answer

A heifer develops cystic ovarian disease after her first estrus

Answer

A bull is exposed to estrogen-contaminated feed during puberty

Question 4

In dogs, a primary reason bitches fail to conceive despite multiple breedings is:

Accepted Answer

Breeding at the wrong time relative to ovulation because canine oocytes require additional maturation time after ovulation

Answer

Breeding too early in proestrus before any LH rise

Answer

Exclusive male infertility with no female contribution

Answer

Excessive progesterone production that prevents fertilization

Question 5

After approximately day 150 of equine gestation, the primary source of progesterone maintaining pregnancy shifts to:

Accepted Answer

The fetoplacental unit

Answer

The primary corpus luteum of pregnancy

Answer

Accessory corpora lutea formed from eCG stimulation

Answer

The adrenal cortex of the mare

Question 6

Pyometra in dogs is most commonly associated with which phase of the reproductive cycle?

Accepted Answer

Diestrus

Answer

Proestrus

Answer

Estrus

Answer

Anestrus

Question 7

The Ovsynch protocol in cattle achieves synchronized, fixed-time artificial insemination by:

Accepted Answer

GnRH injection to initiate a new follicular wave, followed by PGF2α to lyse the CL, then a second GnRH to induce ovulation

Answer

Progesterone implant for 7 days followed by estradiol benzoate to synchronize estrus

Answer

Repeated FSH injections for superovulation followed by a single LH injection

Answer

Melatonin administration to manipulate photoperiod and reset the cycle