Journal of Veterinary and Animal Sciences

Abstract

A total of 48 repeat breeder cows were divided into three groups viz., group I, II and III. Cows in group I and II were treated with 0.98mg of Tiaprost (PGF2α ) on day 10 following natural oestrus (day 0). Group III cows, served as control without any treatment. AI was done at 72 and 96 h following PGF2α therapy in group I and II. Group III cows were artificially inseminated twice at 24 h interval during natural oestrus. Group II cows were injected with 1500 IU hCG on day four following first AI. There was cent per cent oestrus response in PGF2α treated cows. The mean onset of oestrus was 59.38±0.81 and 59.63±0.74 h and the mean duration of induced oestrus was 28.50±0.56 and 27.50±0.70 h in group I and II, respectively. In control, the mean duration of oestrus was 29.38±0.77 h. The occurrences of very good and good oestrus intensities were 12.50 and 87.50 (group I) and 25.00 and 75.00 (group II and III) per cent. The first service conception rate obtained was 43.75, 37.50 and 18.75 per cent, in group I, II and III, respectively. It is concluded that administration of PGF2α on day 10 following natural oestrus may improve the conception rate in repeat breeder cows and that injection of hCG on day four after fixed time AI is unnecessary.