Reproductive pattern in buffaloes (Bubalus bubalis) is affected by photoperiodicity, heat stress and availability of feed supply. The objectives of this study were to understand the seasonality pattern of breeding and calving in buffaloes in subtropical regions of southern Nepal and to characterize the ovarian cyclicity status during the months of long day length. Data regarding seasonality pattern of breeding and calving of Murrah cross bred buffaloes (n=400) from two locations of subtropical region were collected. In a subset of buffaloes (n=104), the ovarian cyclicity status during late spring (May to June) was determined through transrectal ultrasonography and measurement of blood progesterone concentration using ELISA. Seasonal breeding and calving patterns were similar at two locations. The highest proportions of buffaloes were bred during autumn (40.8%), followed by winter (29.5%), summer (19.8%) and spring (10%). While comparing the month-wise patterns, the highest and the lowest proportions of breeding were in November and April, respectively. Likewise, the highest proportions of buffaloes calved in autumn (41.3%), followed by summer (26.8%), winter (20.8%) and spring (12.8%); the highest and lowest proportions of calving were in September and May, respectively. During the low breeding season, 53% buffaloes were non-cyclic (true anestrous) as indicated by inactive ovaries and below basal level (<1ng/ml) plasma progesterone concentration. In conclusion, there was a clear seasonality pattern of reproduction in buffaloes in subtropical regions of southern Nepal with the autumn being the good and the spring being the low breeding as well as calving seasons; and 53% of buffaloes during low breeding season were in true anestrous condition.
Keywords | Buffalo, Reproduction, Seasonality, ELISA, Progesterone, Anestrus