DIGESTIBLE ENERGY REQUIREMENTS FOR MAINTENANCE OF BODY MASS OF WHITE-TAILED DEER IN SOUTHERN TEXAS

Previous experiments designed to estimate daily digestible energy requirements for body-mass maintenance in white-tailed deer (Odocoileus virginianus) were conducted using deer adapted to northern environments. However, animals adapted to warmer, drier environments may have lower metabolic requirements than their temperate conspecifics. We conducted a feeding trial to estimate digestible energy requirements for maintenance of body mass of white-tailed deer in southern Texas and to determine if those requirements vary over time. By restricting dietary levels of digestible energy and measuring deer body mass every 3 days for a 30-day period, we developed a model relating digestible energy intake and change in body mass over time for 11 adult, nongravid females during autumn. Predicted daily digestible energy intake requirements for body-mass maintenance (kJ/kg body mass super(0.75)) ranged from 820 plus or minus 168 SE at trial initiation to 357 plus or minus 42 at trial completion. Our experiment demonstrated that daily digestible energy maintenance requirements decline during extended periods of energetic restriction and that values previously reported may overestimate the requirements for deer in southern latitudes.