Effects of prostaglandin and HCG on out of season oestrous synchronization and fertility and assessment of progesterone concentration for early pregnancy diagnosis in ewes

Abstract

The study investigates the possibility of oestrus synchronization in ewes of MIS sheep population using prostaglandin (PG) outside the breeding season, serum progesterone concentration for pregnancy diagnosis and effect of hCG (human chorionic gonadotropin) on reproductive parameters. Prostaglandin was used to induce oestrus at the dose of 2.5 ml/ewe, administered intramuscularly in two injections (with 11 days interval). Responsive ewes were bred to rams and were divided into two groups, one of which was administered with hCG at the dose of 300 IU i/m 7th day post mating and the second group which was used as a control. Serum progesterone was measured on the day of prostaglandin administration and 17 days post mating. Oestrus response was 66.67%, lambing rate was 70%, average litter size was 1.7 lambs/ewe and twinning rate was 60%. Administration of hCG 7 days post mating did not improve fertility results. Lambing, prolificacy and twinning rates were higher in control than in hCG group, but no statistical difference was found between these groups. From a total of 20 ewes that were mated after PG treatment in 18 of them (90%), on the basis of progesterone concentration measured on the 17th day after mating and subsequent lambing results, gestation was confirmed or denied.