Animal Nutrition & Veterinary Physiology

Anatomy and physiological asymmetry of bovine ovaries:

• Statement (I) is correct: Buffalo ovaries are distinctly smaller, lighter ($3\text{ to }4\text{ g}$ vs $8\text{ to }10\text{ g}$ in cows), and possess fewer primordial follicles.
• Statement (II) is incorrect: In both cows and buffaloes, the right ovary is physiologically more active ($60\%$ of ovulations occur on the right side) and slightly larger than the left ovary, not smaller.
• Thus, Statement (I) is correct and Statement (II) is incorrect.
• Therefore, option 3 is the correct answer.

Terminology of reproductive milestones:

• Puberty is the age or physiological stage at which the gonads and secondary sex organs become functional, first viable gametes are produced, and the animal becomes capable of successful reproduction.
• Fecundity refers to the potential reproductive capacity or litter size.
• Mating is the act of copulation.
• Spermiogenesis is the maturation of spermatids into spermatozoa.

Chronological progression of the mammalian estrous cycle:

• Phase 1: Proestrus (follicular growth driven by FSH with rising estrogen).
• Phase 2: Oestrus (estrus, peak estrogen causing sexual receptivity and LH surge).
• Phase 3: Metestrus (post-ovulation, formation of corpus luteum, progesterone secretion initiates).
• Phase 4: Dioestrus (mature corpus luteum dominates with high progesterone).

Both Assertion (A) and Reason (R) are correct, and (R) is the exact physiological explanation of (A):
In the nephron, the loop of Henle is divided into thin descending, thin ascending, and thick ascending segments.
The overall outer wall diameter differs markedly because the thin limbs are lined by simple squamous epithelium (thin cell profile), whereas the thick ascending limb is lined by cuboidal epithelial cells with abundant mitochondria.
However, the internal luminal diameter remains relatively constant along these segments. Hence, the difference in limb thickness reflects cellular wall height rather than luminal narrowing or dilation.

Option breakdown:

• Both (A) and (R) are true and (R) correctly explains (A).
• (R) directly explains the morphological basis of (A).
• (R) is not false.
• is not false.