Effect of duration of biostimulation on oestrus expression, resumption of ovarian activity, conception rate and peripheral cortisol level in postpartum anoestrus Nili-Ravi buffalo during low breeding season

Abstract

The aim of experiment was to evaluate whether biostimulation by mature intact bull to anoestrus buffalo alters breeding performance associated with CIDR based oestrus synchronization protocol during low breeding season. Anoestrus buffalo that had calved 170.0±10.6 (132 to 208) days before the start of the trial, were either exposed to bull (n=30, BE) or not exposed to bull (n=10, BN) for 12 days after CIDR placement (day 0). Animals received PGF_2α on day 9, CIDR was removed on day 10 and Timed AI (TAI) was performed with frozen thawed semen at 48 and 60 h after CIDR removal. Buffalo were observed for oestrus detection twice daily for three days after CIDR removal. Blood sampling was done on day 9, 12 and 20 of the experiment to monitor the progesterone and cortisol levels (5 per group). Pregnancy test was done 60 days after insemination. Oestrus expression was noted in 68.97% (BE) and 60% (BN) animals (P>0.05). Progesterone rise above 1 ng/ml on day 20 was recorded in 4/5 (80%) in BE group and 2/5 (40%) in BN group (P>0.05). Conception rate was 37.9% (11/29) and 30%, (3/10) in BE and BN groups respectively (P>0.05). It is concluded that CIDR and fixed time artificial insemination can be used to overcome partially the problem of anoestrus and seasonality in buffalo. However, biostimulation in CIDR treated anoestrus buffalo did not increase the number of ovulating/oestrus buffalo during low breeding season probably due to a shorter exposure period (only 12 days) to bull.