Some reproductive characteristics of the Peulh ewe from Niger. The duration of the oestrous cycle, oestrous, pregnancy and post-partum anoestrus, as well as the kinetics of plasma progesterone and prolactin levels during each of those periods, were studied in ewes of a tropical breed without wool. The value of the parameters and the profiles of the two hormones were comparable to those of other European and tropical breeds, suggesting that the Sahelian climate has little to do with the sexual endocrinology of the sheep. Introduction.