UTTAR PRADESH JOURNAL OF ZOOLOGY

Repeat breeding is one of the exasperating reproductive disorders of dairy cows which results in heavy economic loss to dairy farmers.  The present research was conducted to compare the efficacy of different oestrous synchronization protocols in repeat breeder cows under field condition. A total of 50 repeat breeder cows formed the experimental animals for the present study. The repeat breeder cows were randomly and equally assigned to one of the five groups. viz. CIDR (Group I; n=10), Ovsynch (Group II; n=10), Ovsynch+CIDR (Group III; n=10), Ovsynch+CIDR+Vitamin AD3E&H (Group IV; n=10) and Control (Group V; n=10) and bred accordingly. The pregnancy status was checked 45 days post insemination by rectal palpation. The estrus induction response and conception rate in all five groups are compared and analysed. Though cows from all groups expressed estrus, there was significant difference (P≤0.05) in their duration of estrus which was high in Group IV. The overall conception percentage obtained in Group I, II, III, IV and V were 30, 40, 60, 80 and 20 per cent, respectively. In this study, the highest overall percentage of conception rates were recorded in group IV (80.00) followed by group III (60.00) when compared to groups II (40.00), I (30.00) and Control (20.00). Hence, it is concluded from the present study that Ovsynch+CIDR+Vitamin AD3E&H protocol resulted in better estrus expression, duration and conception rate for treatment of repeat breeder cows under field conditions than other protocols.