USE OF PROSTAGLANDIN (PGF2α) TO INDUCE OESTRUS IN POSTPARTUM SAHIWAL COWS

Twenty-four postpartum Sahiwal cows that did not show oestrus upto 85 days postpartum were randomly divided into two equal groups, A and B. Group A cows were injected 2 ml Prostavet injection containing 5 mg Etiproston, a synthetic analogue of PGF2α (Virbac, France) intramuscularly at day 85 postpartum on chronological basis of calving dates without palpation. A second injection was given 11 days later to those cows that did not respond to first injection. A third injection was given at 118 days postpartum to those cows that had not responded to 1st and 2nd injection of PGF2α and did not show oestrus. The cows in group B were not given any treatment and served as control. The cows found in oestrus were artificially inseminated 12 hours after the detection of oestrus. The cumulative oestrus response was higher (66.66%) in group A than in group B (25%). Similarly, in group A the behavioral symptoms and physical changes were more pronounced as compared to group B. Mean ( ± SE) interval from treatment to onset of oestrus in group A was 96 ± 15.08 hours whereas, mean interval to oestrus from beginning of experiment was 25.0 ± 1.0 days in group B. Statistically non significant difference was observed in the mean duration of oestrus (23.25 ± 1.99 vs. 20.33 ± 1.45 hours) between animals of the two groups. However, a significant (P<0.05) difference was observed for the mean calving to first oestrus interval (89 ± 0.62 vs. 110 ± 0.19 days) in groups A and B. From the results, it is concluded that PGF2α is useful for treatment of unobserved oestrus in postpartum Sahiwal cows