A preliminary report on regulation of oestrus and fertility in cyclic ewes by an oral administration of 6-methyl-17-acetoxyprogesterone

Abstract

A preliminary investigation has been carried out to test the value of 6-metbl-17-acetoxjprogesteron (MAP) as a suppressor of ovarian activity. The progesterone derivative (MAP) was given to Merino ewes for 16 days during the breeding season. It was fed at s rate of 50 mg a day in 1/2 lb crushed wheat (group 1) or administered in capsule form at the rate of 50 mg a day (group 2a), 100 mg every two days (group 2b) or 200 mg every four days (group 2c). Suppression and synchronization of oestrus and conception were satisfactory in group 1, 2a and 2b, but not in 2c. In groups 1, 2a and 2b, 37 ewes were treated, 30 (eighty one per cent) muted in a space of three days and 25 (sixty eight per cent) of these. were found pregnant at slaughter. These results suggest that administration of MAP at a rate of 100 mg every two days will be followed by satisfactory synchronization of oestrus and normal conception rates.