Time of Ovulation in Ewes after Treatment with a Prostaglandin F-2 {Alpha} Analogue

Summary. Treatment of 18 cyclic Clun Forest ewes with two i.m. injections of ICI 80,996, given 9 days apart and without reference to stage of the oestrous cycle, synchro-nized ovulation in all ewes at a mean time interval of 73\m=.\1\m=+-\1\m=.\6(s.e.m.) h from the second injection. The interval from the LH peak to ovulation was 22\m=.\6\m=+-\0\m=.\7h and this is comparable to previously reported figures for a natural oestrus