No abstract

Eighty-four Awassi ewes in five groups were used to study the effect of using different hormonal treatments or ram effect on oestrus synchronisation and fertility at the beginning of the breeding season. At the onset of the treatments, gonadotropin releasing hormone-prostaglandin F 2α (Gn-PG, n = 17) ewes received gonadotropin releasing hormone (GnRH) i.m. followed with prostaglandin F 2α (PGF 2α) 5 days later. Ewes in the prostaglandin F 2α-prostaglandin F 2α (PG-PG, n = 20) group received two i.m. injections of PGF 2α 10 days apart. Ewes in the fluorogestone acetate (FGA, n = 15) group were fitted with FGA intravaginal pessaries, left for 14 days and given an i.m. injection of pregnant mare serum gonadotropin (PMSG). Ewes in hormonal treatments (Gn-PG, PG-PG, FGA) and the Close (n = 17) group, were housed in a barn close to the rams' barn for the last 15 days, while those in the Far (n = 15) group were left in a barn completely separated from rams until the day of mating. Ten fertile rams were introduced 48 h after the last treatments. Plasma progesterone (P4) concentrations were similar at the onset and at the last day of A05026; Online publication date