Seasonal variation in follicular dynamics of superovulated Indian water buffalo.
The ovaries of 5 buffalo were examined daily by ultrasound beginning at Day 3 of the estrous cycle, followed by superovulation between Days 11 and 13 of the cycle in both the wet cool and dry hot seasons. Daily ultrasonographic observations of the ovaries were recorded on a videotape and were used to assess the progression of both the large (dominant) and the next to the large (sub-dominant) follicles as well as the numbers of follicles in the small (4 to 6 mm), medium (7 to 10 mm) and large (> 10 mm) size categories in the 2 seasons before and during the superovulation treatment. Greater numbers of small (P < 0.05) and medium size follicles (P < 0.01) were available before the start of the superovulatory treatment in the buffalo during the dry hot season. The turnover of follicles from medium to large size classes also occurred sooner (P < 0.01) and was of higher magnitude (P < 0.05) during the treatment in the dry hot season. However, the number of corpora lutea at palpation per rectum (2.8 +/- 0.7 vs 2.2 +/- 0.6), the serum progesterone concentration (1.6 +/- 0.3 vs 1.4 +/- 0.1 ng/ml), and the yield of embryos on Day 6 (0.2 +/- 0.2 vs 0.6 +/- 0.2) did not differ significantly between the dry hot and the wet cool season. None of the embryos recovered during the dry hot season were transferable, which remains unexplained.
Taneja
M
M
Embryo Biotechnology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067 India.
Totey
S M
SM
Ali
A
A