Management of reproductive seasonality in small ruminants

Abstract

The majority of the species of small ruminants are seasonal reproducers, which implies that there are changes in their reproductive physiology that determine the existence of a reproductive season, in which the females cycle and ovulate and the males present their maximum reproductive activity, and an anestrus season, in which the females do not present estrous cycles and the males decrease their level of reproductive activity. The reproductive seasonality is an evolutionary consequence of the species so that the births occur at the most favorable moment for the survival of their offspring, which in temperate climates usually occurs in the spring. In the case of rams and goats there are annual variations in the concentration of LH, FSH and testosterone, which generates changes in the characteristics of semen and sexual behavior. For example, during the reproductive season the diameter of the seminiferous tubules and the epididymis increases, the number of spermatogonia in the seminiferous tubules, and the size, weight and activity of the secondary sex glands. This determines that the males of many breeds of sheep and goats have a low capacity to breed female cycling during this period.