Enhancing off-season fertility in dairy buffaloes through monensin supplementation

Abstract

Ninety suboestrus, pluriparous, Murrah buffaloes (60–180 days post-partum) reared under semi-intensive system
formed the subject of this study. These buffaloes failed to exhibit overt oestrus and remained un-bred. The buffaloes
were subjected to synchronized breeding using modified ovsynch protocol which included 5 ml receptal (20 μg buserelin) on day 0, 2 ml vetmate (500μg cloprostenol) on day 7 and 2.5 ml receptal (60 h after cloprostenol) on day 9, injected intramuscularly. Fixed time AI was done at 16 and 40 h after the last injection. Some of the buffaloes which returned to oestrus about 15–21 days later were served naturally. The pregnancy was diagnosed 90 days later through rectal palpation of genitalia. In the first phase, buffaloes were synchronized and bred either in the favourable breeding season (October through March; n= 40) or in the unfavorable season (April through July; n=40). The first service and the overall conception rates were 30 and 37.5% (during unfavourable season) and 55 and 65% (during favourable season; P<0.05), respectively. Assuming that poor quality and low quantity of the fodder availability in the unfavorable period, the second phase of the study incorporated oral supplementation of 200 mg monensin (an ionophore) per animal per day (n=10) for 30 days
before and during the application of synchronized breeding. The first service and the overall conception rates increased
substantially to 50 and 80%, respectively. Average follicular diameter 36 h after the cloprostenol injection in the buffaloes
that conceived (5) or remained un-conceived (5) were   similar (9.99±0.33 vs 8.45±0.56 mm). Supplementation     of monensin did not affect the quality of the milk. It is concluded that supplementary feeding of monensin substantially improved fertility in suboestrus buffaloes following their management through ovsynch synchronization and fixed time insemination during off-season.