Ovarian changes and follicular dynamics during postpartum period in Murrah buffaloes

The study was conducted on twelve normally calved, suckled, lactating Murrah buffaloes, aged 57.9 ± 3.2 months from 1st to 3rd parity. The animals varied from 12 to 30 days postpartum at the start of experiment and suckling was restricted to twice daily (before milking). The objective of the study was to monitor ovarian follicular changes during early postpartum in Murrah buffaloes using a real time B-mode ultrasonography. Only 3 out of 12 animals showed cyclicity during observation period. Large follicles (8 to 10 mm) were detected for the 1st time at 24.4 ± 1.99 days, whereas >10 mm follicles were first noticed at 26.0 ± 1.41 days. The duration of growth of dominant follicle (9.3 ± 0.48 days) was higher than duration of its regression (7.1 ± 0.40 days), thereby indicating that the rate of regression is faster (0.73 ± 0.03 mm/d) as compared to rate of growth (0.64 ± 0.02 mm/d). The duration of growth of corpus luteum formed after 1st ovulation was very short (8.67 ± 1.44 days). The largest diameter attained by first postpartum ovulatory follicle was 13.0 ± 1.10 mm and the calving to first postpartum ovulation interval was 52.67 ± 8.02 days in the present study. It is concluded that very few (25%) buffaloes experience ovulations in early postpartum period (within 2 months postpartum). Low number of buffaloes displayed spontaneous resumption of postpartum cyclicity although ovaries of all the animals exhibited follicular activity.