Effects of Seasonal Protein Restriction on Antlerogenesis and Body Mass in Adult Male White-Tailed Deer

Seasonal dynamics in protein availability vary with latitude throughout the geographic range of white-tailed deer (Odocoileus virginianus), but the effects of variability in the timing of protein availability on deer performance or antlerogenesis are understood poorly. We designed an experiment to examine the effects of a 12-week (spring or summer) protein restriction on deer performance. Eighteen male white-tailed deer (≥2 yr old) were blocked by past antler size, body mass, and age, then randomly assigned to one of 3 diet groups (LH, HL, HH) composed of 2 dietary levels of crude protein (CP), low (L, 7%) or high (H, 16%) during 1992-93. The HH group served as the control, receiving a high protein diet during the antlerogenic period (Mar-Aug) of each year. The LH and HL groups received a low protein diet for a 12-week period in spring (LH) or summer (HL) and a high protein diet in the opposite season. During fall and winter, all deer consumed a medium protein diet created by mixing the experimental diets. Body mass, feed intake, antler characteristics, and serum chemistries were examined. No diet effects were found for any antler characteristic measured. Body mass varied by a diet-month interaction in 1992 (P = 0.04) and in 1993 (P = 0.01), because deer on H diets from June to September gained mass faster than deer on L diets for the same period. Rapid gain of body mass was accomplished by increased feed efficiency rather than increased feed intake. Final body mass did not vary by diet (P = 0.587). In general, serum chemistry levels were consistent with those reported in the literature. Adult white-tailed deer compensated for a 12-week protein restriction within a 5-17-week realimentation period. Greater treatment effects during the second year of the study suggested cumulative effects of protein restriction on deer performance.