DOSE DEPENDENT EFFECT OF PROSTAGLANDIN ANALOGUE IN DOUBLE INJECTION REGIMEN FOR ESTRUS SYNCHRONIZATION IN GOATS

The present study was conducted on 60 goats of Nachi breed to ascertain the effectiveness of different doses of cloprostenol for estrus synchronization with the double prostaglandin injection regimen. Does were randomly divided into three groups (A, B and C) comprising of 20 animals in each group. In all three groups of does, two intramuscular injections prostaglandin analogue i.e. cloprostenol (Dalmazine, FATRO-Pharmaceutical Veterinary Industry, Italy) were given at an interval of 10 days with different dosage rate i.e. Group A; 75 μg, Group B; 112.5 μg, Group C; 150 μg, respectively. The expression of estrus behaviour after administration of first injection of cloprostenol ranged from 70 to 75% in group A, B and C does whereas after second injection, the estrus behavior was 95% in all three groups of does. There was nonsignificant difference in expression of estrus behaviour subsequently one or two injections of cloprostenol. The time interval after cessation of treatment to onset of estrus differed significantly (P<0.05) and the estrus duration was shorter for all three treatment groups of does after first injection of cloprostenol in comparison with after second injection of cloprostenol. The pregnancy rate was significantly higher in does treated with lower doses (75 μg) of cloprostenol in comparison with higher doses (112.5 & 150 μg) of cloprostenol. It was concluded that the lowest dose of cloprostenol (75 μg) explored, is appropriate for estrus synchronization in the double injection regimen.