Nitrogen requirements for antler growth and maintenance in white-tailed deer

Data describing nitrogen (N) requirements for maintenance and production in adult male cervids are limited. We used balance trials (n = 72) and regression analysis to estimate N requirements for maintenance and production (i.e., antler development) in adult (>2-yr-old) white-tailed deer (Odocoileus virginianus). Nitrogen deposition in antlers was estimated and included in balance calculations. Minimal maintenance and average growth requirements (+/- 2 SE) for N during the antler growth period (Apr-Aug) were 0.61 (+/- 0.16) and 1.06 (+/- 0.15) g N/kg(0.75)/day, respectively. At intake rates observed in this study, these requirements are equivalent to erude protein requirements of 5.8 and 9.9% for maintenance and growth, respectively. Minimal maintenance and average growth requirements for N during winter (Oct-Feb) were 0.37 (+/- 0.33) and 0.92 (+/- 0.30) g N/kg(0.75)/day, respectively. At intake rates observed in this study, these requirements are equivalent to erude protein requirements of 4.1 and 10.1% for maintenance and growth, respectively. We discuss shortcomings of balance trials to measure N requirements, such as the need to quantify all sources of N loss.