Dietary and Seasonal Influences on Nutritional Indices of Adult Male White-Tailed Deer

Abstract

Nutritional and seasonal influences on physiological indices of nutritional status were determined in a 1-year experiment with 10 male white-tailed deer (Odocoileus virginianus). The deer were placed on ad libitum or 0.75 ad libitum diets and sampled every 28 days. Voluntary feed intake decreased in October. Body weights peaked in October, reached their lowest level in April, and were greater for ad libitumthan restricted-fed deer. Hemoglobin concentration, packed cell volume, and mean corpuscular hemoglobin content (MCHC) varied monthly; only MCHC was significantly lower in restrictedthan in ad libitum-fed deer. Interactions between study months and diets were observed for blood urea nitrogen and urinary urea nitrogen/creatinine ratios. Significant seasonal variation was observed for serum cholesterol, regardless of level of feeding. Ketone-body concentrations in serum were greater for ad libitumthan restricted-fed deer during the last 4 months of the study. J. WILDL. MANAGE. 45(4):926-936 The use of physiological indices of nutritional status in wild cervids has received much attention in wildlife science. However, before these nutritional indices can be reliably and accurately applied in the field, controlled experiments must be conducted to identify and minimize environmental influences that may lead to alterations in physiological characteristics. Uncontrolled observations may lead an investigator to erroneous conclusions. Kirkpatrick et al. (1975) and Seal et al. (1978a) examined nutritional indices of white-tailed deer fawns under controlled conditions. However, Kirkpatrick et al. (1975) examined only blood urea nitrogen (BUN), and Seal et al. (1978a) conducted their experiment for only 10 weeks. Long-term experiments, similar to that of Bahnak et al. (1979), permit the determination of seasonal variations in physiological indices and thus provide additional valuable information. The objective of our experiment was to identify variations in nutritional indices of adult m le white-tailed deer in response to season and a 25% dietary restriction in a 1-year study. This study was supported in part by a grant from the Pratt Animal Nutrition Foundation at Virginia Polytechnic Institute and State University. Technical assistance was provided by D. Gibson, T. Jones, W. Morehead, J. Dickinson, and H. Warren. U. S. Seal provided assistance in developing the nonesterified fatty acid procedure.