Reproductive Responses to Nutritional Stress in Adult Female Collared Peccaries

Abstract

The influence of nutrition on adult female collared peccary (Tayassu tajacu) breeding activity during the peak breeding season in Texas was studied under controlled conditions. Thirteen captive adults were fed either a high quality (15.2% crude protein and 3,300 kcal digestible energy/kg) or low quality (6.3% crude protein and 1,921 kcal digestible energy/kg) diet beginning 25 October 1983. The low quality diet simulated the energy and protein intake of an adult female during drought range conditions. During the peak breeding season (Jan-Feb) in 1985, a daily breeding program was implemented to monitor estrous behavior and fertility. All females were sacrificed after approximately 15 weeks. Three of 6 receiving the low quality diet showed no behavioral signs of estrus, whereas all females fed the high quality diet were bred. Duration of estrus averaged 1.3 and 3.5 days for cycling females on low and high quality diets, respectively. Only 1 of the 3 cycling females on the low quality diet became pregnant, whereas 6 out of 7 cycling females on the high quality diet became pregnant. Ovarian examination revealed <50% of the females receiving the low quality diet for 10 weeks entered the peak breeding season in an anestrous condition. This study suggests that prior nutritional stress among wild females will greatly influence the incidence of pregnancy and, hence, recruitment of young into the herd. J. WILDL. MANAGE. 50(2):295-300 Although the adult female collared peccary is a polyestrous breeder (Sowls 1966), the majority of breeding occurs during DecemberMarch in the southwestern United States. Field studies have shown substantial decreases in herd recruitment during periods of below average rainfall (Low 1970, Bissonette 1982, Sowls and Maurer 1985), presumably as a result of decreased quality or quantity of nutritionally adequate foods. Currently it is not known where in the peccary reproductive cycle potential recruits are lost or which physiological states are ost affected by nutritional stress mediated by rainfall. Recent observations support the hypothesis that nursling postnatal survival and ovarian activity are susceptible to periods of nutritional stress. Bissonette (1982) indicated postnatal mortality of nurslings contributed to low recruitment in southwestern Texas peccary populations. Few conceptions occur during summer, and seasonal delays in onset of peak breeding have been observed when range con'Present address: Department of Zoology, Oklahoma State University, Stillwater, OK 74078. This content downloaded from 157.55.39.102 on Mon, 03 Oct 2016 06:14:36 UTC All use subject to http://about.jstor.org/terms 296 PECCARY REPRODUCTIVE RESPONSES * Lochmiller et al. J. Wildl. Manage. 50(2):1986 Table 1. Ingredient and chemical composition of pelleted, experimental diets fed ad libitum to pregnant collared peccaries in southern Texas, October 1983-February 1984.