Pardeep SinghMalik, Rakesh Kumar2017-08-052017-08-052005http://krishikosh.egranth.ac.in/handle/1/5810027598Resumption of postpartum ovarian activity is essential for continued cycle of reproduction in order to achieve maximum lifetime production from dairy animals. However, in buffaloes, this period is often intercepted by long periods of ovarian quiescence with serious economic consequences. Therefore, the phenomenon of ovarian follicular turnover during early postpartum period (day 12 - 78) was studied in 12 Murrah buffaloes at an organised farm with alternate day transrectal ultrasonography of ovaries. The study revealed that though the dynamic follicular turnover continued in wave pattern during the early PP period, it was largely suppressed. As the postpartum period increased, the mean diameter of DF in a wave also showed significant progressive increase from 7.40±0.44 mm during <30 days pp to 11.02±0.71 mm in > 60 days pp. Yet, only 3/12 buffaloes ovulated during the period, indicating high incidence of postpartum anestrus – as also indicated by basal plasma progesterone profiles. Maximum diameter of the ovulating follicle was 13.03±1.06 mm with growth rate of 0.83±0.05mm/day and interval from wave emergence to ovulation was 14.0±1.6 days. A total of 52 anovulatory waves were recorded with maximum diameter of DF being 10.24±0.26 mm and growth rate of 0.65±0.02 mm/day. Second part of the study involved assessment of two estrus induction protocols – Crestar-eCG and Ovsynch-Plus (eCG-GnRH-PGF2α-GnRH-FTAI) in two groups of anestrus buffaloes with PP intervals of around 2 or 8 months. Crestar treatment initially exerted a suppressive effect on follicular profiles, but implant withdrawal was followed by accelerated follicular growth, aided by eCG administered at implant withdrawal, leading to ovulations in 14/15 treated buffaloes. Ten buffaloes conceived at induced estrus and three more at subsequent inseminations. Ovsynch-Plus treatment was not so successful. Though ovulations were recorded in all treated buffaloes in response to the first GnRH following initial eCG, but some resulting CL were short-lived leading to lower synchrony of ovulations following 2nd GnRH and lower conception rate of 20% (3/15) to fixed timed inseminations. In conclusion, the problem of postpartum anestrus is rampant in buffaloes due to failure of ovulations in DFs, though it can be managed with suitable hormonal therapies like Crestar+eCG.enThesis