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The aim of this study was to assess the synchrony in follicular wave emergence and subsequent ovulation following dominant follicle ablation or estradiol-17β administration. Six cycling Murrah buffaloes were sequentially allotted to three groups, that is, control, follicular ablation, and estradiol-17β groups. For the control group, buffaloes at random stages of estrous cycle were examined daily by transrectal ultrasonography for 14 days and the day of wave emergence was recorded. Following induced luteolysis and ovulation (Day 0), these buffaloes were included in the ablation group. All follicles (>5mm) were ablated on Day 3 or 5 or 7 (n=2 each day). Seven days after the ablation, these buffaloes were administered prostaglandin F2α to induce luteolysis and ovulation. Following this, buffaloes were included in the estradiol treatment group with estradiol administered on similar days as for ablation in the ablation group. Luteolysis was induced nine days after the estradiol injection. All animals of the treatment groups were subjected to transrectal ultrasound and blood samplings daily from treatment to induced ovulation. The follicular waves emerged significantly earlier (P=0.001) in both the ablation (2.1±0.79 days) and estradiol (4.0±0.25 days) treatment groups than the control group (8.3±0.88 days). The deviation from mean day of ovulation was greater (P=0.02) for the control group buffaloes (1.66±0.3 day) than those of the treatment groups (ablation, 0.76±0.2 and estradiol, 0.58±0.2 day). In conclusion, both ablation and estradiol resulted in synchronous emergence of a new follicular wave irrespective of stage at which the treatment was given, with greater synchrony of ovulations in water buffalo., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Luteolysis of corpus luteum, due to un-inhibited PGF(2α) secretion, has been reported to be a cause of early embryonic mortality in dairy animals. The objective of this study was to determine the effects of fish meal (FM) supplementation on the uterine secretion of PGF(2α) and hence establish its supplementation as an antiluteolytic strategy in dairy buffaloes. Five cycling Murrah buffaloes were supplemented with 250g FM daily for 55 days in addition to their routine feed and seven buffaloes were kept as non-supplemented control. After 30 days of FM supplementation, the oestrus was synchronized in all the buffaloes using Ovsynch protocol. On day 15 of synchronized cycle, animals were challenged with oxytocin (OT; 100IU) intravenously and blood samples were collected at 15min interval, 1h before to 4h after OT challenge. The PGF(2α) response was measured as the venous concentration of 13,14-dihydro-15-keto PGF(2α) (PGFM). The mean hourly concentration of PGFM in FM supplemented buffaloes was lower than in the control buffaloes at all the occasions. During peak response (1h post-OT challenge), PGFM concentration was significantly lower (P<0.05) in FM supplemented buffaloes than in the control (197.4±41.7pg/ml versus 326.3±33.5pg/ml, respectively). Also the percent rise in PGFM after OT-challenge in FM supplemented buffaloes was less than the control (11.73% versus 22.47%). The dietary supplementation did not affect the size of corpus luteum (CL) and plasma progesterone concentration. Plasma glucose and total protein concentrations remained within the normal physiological limits during FM supplementation. The present study indicated that supplementing FM decreased the concentrations of PGF(2α) without alterations in the size of CL and plasma progesterone concentrations in dairy buffaloes., (Copyright © 2011 Elsevier B.V. All rights reserved.)