Reevaluation of the Basal Metabolic Cycle in White-Tailed Deer

Abstract

We investigated the seasonal cycle of basal metabolism in white-tailored deer (Odocoileus virginianus) by measuring basal metabolic rate (BMR) of four nonpregnant and four pregnant does from winter to summer. Metabolism was measured monthly with indirect respiration calorimetry from January-July/August, 1989. Mean monthly BMR of nonpregnant does ranged from 85.5 to 89.0 kcal/kg body weight 0.75/day. The mean BMR of nonpregnant does was 87.1 kcal. Individual, nonpregnant BMR, averaged across all months, varied from 80.7 to 93.5 kcal with minimal monthly or seasonal change. Metabolism of pregnant does increased curvilinearly from January to parturition. Postpartum BMR averaged 86.4 kcal, similar to nonpregnant does. Our data are similar to prior winter measurements of BMR, but are substantially lower than previously reported summer BMRs. Our data do not support the proposed existence of an inherent seasonal cycle in basal metabolism in white-tailed deer. Experimental temperatures and animal activity within metabolism chambers may have affected previous summer measurements