Free Theriogenology and Animal Reproduction MCQs with Answers
59 Theriogenology and Animal Reproduction MCQs from Veterinary Science, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Covers the reproductive anatomy and physiology of male and female domestic animals, including puberty, oestrous cycles, ovulation, fertilisation, pregnancy, parturition and lactation. It also includes artificial insemination, semen evaluation, pregnancy diagnosis, infertility, dystocia and reproductive disorders, with attention to species differences.
Last updated
59 questions · page 3 of 3
- A. Absence of observable or ovarian oestrous activity
- B. Failure of fertilisation after repeated mating
- C. Abnormal enlargement of the pregnant uterus
- D. Inflammation of the uterine lining after birth
Explanation: Anestrus means a period of reproductive quiescence in which oestrous cycles are absent or not detectable.
Correct answer: Absence of observable or ovarian oestrous activity- A. Oestrogen after follicular growth
- B. Progesterone during the luteal phase
- C. Oxytocin during cervical relaxation
- D. Prostaglandin during follicular atresia
Explanation: Pyometra commonly develops during progesterone-dominated diestrus, when uterine glandular secretion and reduced uterine defence favour…
Correct answer: Progesterone during the luteal phase43. Which substance is commonly added to semen before freezing to protect sperm cells from cryoinjury?
- A. Prostaglandin as a luteolytic agent
- B. Oxytocin as a motility stimulant
- C. Glycerol as a cryoprotectant
- D. Heparin as a capacitation inhibitor
Explanation: Glycerol protects sperm membranes and reduces cellular damage caused by ice formation during freezing and thawing.
Correct answer: Glycerol as a cryoprotectant- A. A uterine cycle several weeks ahead of the donor
- B. A pregnancy older than the transferred embryo
- C. A corpus luteum absent throughout the cycle
- D. A reproductive stage closely synchronized with the donor
Explanation: The recipient's uterus must be at a stage that matches the age and developmental requirements of the transferred embryo.
Correct answer: A reproductive stage closely synchronized with the donor- A. Interferon tau to prevent luteolysis
- B. Relaxin to initiate cervical closure
- C. Oestrogen to destroy the corpus luteum
- D. Oxytocin to maintain uterine contractions
Explanation: Bovine conceptus interferon tau suppresses endometrial luteolytic signalling, especially oxytocin receptor expression, thereby maintaining…
Correct answer: Interferon tau to prevent luteolysis- A. Long axis to the long axis of the dam
- B. Head and limbs to the fetal body
- C. Dorsal surface to the maternal pelvis
- D. Placenta to the uterine implantation site
Explanation: Fetal posture describes the disposition of the head, neck and limbs in relation to the fetal body.
Correct answer: Head and limbs to the fetal body- A. Flagellar length and swimming speed
- B. Acrosome size and enzyme activity
- C. DNA content within their nuclei
- D. Mitochondrial number in the midpiece
Explanation: X-bearing sperm contain slightly more DNA than Y-bearing sperm, allowing separation after fluorescent DNA staining and flow-cytometric…
Correct answer: DNA content within their nuclei- A. Artificial insemination
- B. Semen collection
- C. Ovarian superstimulation
- D. Embryo transfer
Explanation: Embryo transfer moves an embryo from a donor female to a synchronized recipient female, allowing the recipient to carry the pregnancy.
Correct answer: Embryo transfer- A. Posture
- B. Position
- C. Presentation
- D. Gestation
Explanation: An abnormal posture is caused by flexion or deviation of the head, neck or limbs and can obstruct delivery.
Correct answer: Posture- A. Relaxin
- B. Inhibin
- C. Oxytocin
- D. Prostaglandin F2α
Explanation: Granulosa cells release inhibin, which selectively suppresses FSH secretion from the anterior pituitary.
Correct answer: Inhibin51. In cattle, ovulation usually occurs at approximately what time after the end of standing oestrus?
- A. 2 to 4 hours
- B. 20 to 24 hours
- C. 10 to 12 hours
- D. 36 to 48 hours
Explanation: In cows, ovulation generally occurs about 10 to 12 hours after standing oestrus ends.
Correct answer: 10 to 12 hours- A. It degenerates before pronucleus formation
- B. It begins meiosis I again
- C. It changes directly into a spermatozoon
- D. It completes meiosis II
Explanation: The secondary oocyte is arrested in metaphase of meiosis II and completes this division after sperm penetration.
Correct answer: It completes meiosis II- A. Sertoli cells
- B. Leydig cells
- C. Peritubular myoid cells
- D. Epididymal principal cells
Explanation: Sertoli cells support developing sperm cells, form the blood-testis barrier, and help regulate spermatogenesis.
Correct answer: Sertoli cells- A. Uterine lavage
- B. Artificial vagina
- C. Vaginal cytology
- D. Transrectal aspiration
Explanation: An artificial vagina provides suitable temperature, pressure, and collection conditions for semen from a stallion.
Correct answer: Artificial vagina- A. Cervix
- B. Vagina
- C. Oviduct
- D. Urethra
Explanation: Early cleavage commonly occurs in the oviduct before the embryo enters the uterus for further development and implantation.
Correct answer: Oviduct56. Which hormone is most directly responsible for milk ejection during suckling in domestic mammals?
- A. Prolactin
- B. Oestrogen
- C. Progesterone
- D. Oxytocin
Explanation: Suckling stimulates oxytocin release, causing contraction of myoepithelial cells around the mammary alveoli and milk ejection.
Correct answer: Oxytocin- A. Puerperal metritis
- B. Ovarian hypoplasia
- C. Vaginal prolapse
- D. Follicular atresia
Explanation: Puerperal metritis is an acute postpartum infection involving the uterus and is often accompanied by fetid discharge and systemic illness.
Correct answer: Puerperal metritis- A. To prevent sperm capacitation
- B. To match uterine conditions with embryo age
- C. To increase fetal sex chromosome number
- D. To delay corpus luteum formation
Explanation: The recipient uterus must be at a stage that corresponds closely to the developmental age of the transferred embryo.
Correct answer: To match uterine conditions with embryo age59. Which process produces genetically distinct haploid spermatozoa from diploid primary spermatocytes?
- A. Mitosis
- B. Fertilisation
- C. Meiosis
- D. Implantation
Explanation: Meiosis reduces the chromosome number by half and generates genetic variation through recombination and independent assortment.
Correct answer: Meiosis