[en] A series of experiments were carried out to study the influence of the nutritional level and physical condition of Barbary ewes on their sensitivity to the male effect, reproductive performance and the intensity of seasonal anoestrus. The results show that undernourishment of ewes during gestation and/or lactation leads to a deterioration of their physical condition, increases the intensity of seasonal anoestrus and alters the quality of their corpus luteum (corpora lutea) induced by the male effect. These effects persist even when these females are overfed between the dry period and the introduction of rams in spring. However, improvement in the nutritional level of such ewes before mating appreciably raises their ovulation, fertility and prolificacy rates. (author). 25 refs, 2 tabs