This study examined the influences of moderate restrictions in maternal energy and protein intake during gestation on reproductive success and foetal development in the Collared peccary (Tayassu tajacu). Sixteen captive females from southern Texas were bred during January 1983 and randomly assigned to one of four experimental rations for the duration of gestation. Experimental diets were formulated in a factorial design with two levels of energy (HE = high, ME = moderate) and protein (HP = high, MP = moderate). Only females on the HEHP diet gained weight during gestation. Moderate restrictions of energy or protein had no influence on the number of young born alive, litter size, litter weight and length of gestation. Foetal development was only minimally affected by prolonged restrictions in protein intake. This study suggests that nutrition-related prenatal mortality between implantation and parturition may not be the most important mechanism limiting herd recruitment during moderate periods of drought in southern Texas.