The effect of progesterone implants on ovulation and plasma levels of LH, FSH and progesterone in anoestrous ewes.

The effects of 100-mg progesterone implants in anoestrous ewes on plasma progesterone and gonadotrophin levels are described. Implant removal resulted in a surge of plasma gonadotrophins and ovulation, but there was no evidence of behavioural oestrus in 90% of the ewes. These results are discussed.