The effectiveness of medroxyprogesterone acetate (MAP) in synchronizing oestrus and its influence on lambing rate and litter size in crossbred ewes

Abstract

Oestrus was synchronized in crossbred ewes (Djallonke x Sahel F₂ generation) on the Ghana Government /UNDPI FAO Sheep and Goat Project Farm at Ejura. Medroxyprogesterone acetate (MAP), 60 mg, was applied in an antibiotic-treated intravaginal sponge and allowed to remain for 14 days. Pregnant mare serum gonadotropin (PMSG; 500 LU) was injected intramuscularly in one group of ewes on the day of sponge withdrawal. A control group (D) had no treatment. TIle progestaten was effective in synchronizing oestrus and resulted in a compact batch lambing interval. PMSG shortened the interval between sponge withdrawal and the onset of oestrus. It also increased the incidence of multiple births. About 80 per cent of animals in MAP treated groups exhibited oestrus within a three-day period as compared to 33 per cent in the control group and the difference was significant (P<0.01). About 90 pcr cent of animals in the treated groups lambed within a 6-day period as opposed to 45 per cent in the control group. The difference was significant (P<0.01) Fertility was 100 per cent for all the animals.