BCSE Theriogenology and Veterinary Reproduction 2 β Questions and Answers
Question 1: According to the Society for Theriogenology minimum standards, what is the minimum acceptable progressive motility for a bull to pass a breeding soundness evaluation (BSE)?
- 20%
- 30%
- 40% (Correct answer)
- 50%
Correct answer: 40%
A satisfactory BSE result requires β₯30% progressive motility, β₯70% morphologically normal sperm, and adequate scrotal circumference; 40% is a common textbook minimum for individual classification as 'satisfactory'.
Question 2: Which method is considered the gold standard for early pregnancy diagnosis in cattle?
- Rectal palpation at day 25
- Serum progesterone at day 21
- Transrectal ultrasonography at day 25β28 (Correct answer)
- Milk progesterone at day 18
Correct answer: Transrectal ultrasonography at day 25β28
Transrectal ultrasonography can reliably detect a bovine embryonic vesicle as early as day 25β28 with high accuracy and allows assessment of embryo viability.
Question 3: Which sperm morphological defect is classified as a MAJOR defect and would reduce a bull's BSE score?
- Proximal cytoplasmic droplets (Correct answer)
- Distal cytoplasmic droplets
- Slightly bent midpiece
- Minor head shape variation
Correct answer: Proximal cytoplasmic droplets
Proximal cytoplasmic droplets are major defects indicating incomplete sperm maturation, whereas distal droplets are minor defects that may indicate rapid transit through the epididymis.
Question 4: The CIDR (Controlled Internal Drug Release) device used in cattle contains which hormone?
- Estradiol
- Progesterone (Correct answer)
- GnRH
- Prostaglandin F2Ξ±
Correct answer: Progesterone
The CIDR device releases progesterone intravaginally to synchronize estrus by mimicking the luteal phase and enabling precise timed AI protocols.
Question 5: What is the primary cause of freemartinism in cattle?
- Chromosomal trisomy in the female twin
- Vascular anastomosis between twins of opposite sex sharing testosterone (Correct answer)
- Nutritional deficiency during gestation
- Infection with Brucella abortus in utero
Correct answer: Vascular anastomosis between twins of opposite sex sharing testosterone
Freemartinism results from placental vascular anastomoses between male and female twins, allowing testosterone and anti-MΓΌllerian hormone from the male to masculinize the female co-twin.
Question 6: Which progesterone concentration on day 4 post-LH surge (day 4 of diestrus) best confirms successful luteinization in the bitch?
- >2 ng/mL
- >5 ng/mL
- >10 ng/mL (Correct answer)
- >20 ng/mL
Correct answer: >10 ng/mL
Progesterone >10 ng/mL on day 4 post-LH surge confirms that adequate luteinization has occurred and the bitch has ovulated successfully.
Question 7: In the ewe, the breeding season is primarily regulated by:
- Increasing day length (long-day breeder)
- Decreasing day length (short-day breeder) (Correct answer)
- Temperature changes alone
- Pheromone exposure from rams only
Correct answer: Decreasing day length (short-day breeder)
Ewes are short-day breeders whose reproductive activity is stimulated by decreasing photoperiod in autumn, mediated via melatonin signaling from the pineal gland.
BCSE Theriogenology and Veterinary Reproduction 2
According to the Society for Theriogenology minimum standards, what is the minimum acceptable progressive motility for a bull to pass a breeding soundness evaluation (BSE)?