Energy and Protein Influences on Blood Urea Nitrogen of White-Tailed Deer Fawns

Abstract

Nineteen female white-tailed deer fawns (Odocoileus virginianus) were used in a 2 X 2 factorial experiment to determine the effect of 2 levels of energy and 2 levels of protein on food consumption, weight gains, and blood urea nitrogen over a 20-week period beginning when the animals were 3.5 months of age. The 2 levels of ration-digestible energy averaged 2,498 and 3,064 kcal/kg. The 2 levels of protein averaged 9.6 and 18.2 percent. Food consumption tended to be greater in animals on low energy diets but decreased in all treatment groups from November through February. Weight gains were significantly greater (P < 0.05) in animals on high protein diets, but no significant difference was found due to energy. Weight gains decreased significantly (P < 0.01) from the 8th through the 20th week of the experiment. Blood urea nitrogen (BUN) was significantly greater (P < 0.01) in fawns receiving high protein diets than in those receiving low protein. Conversely, fawns on high energy intakes had significantly lower (P < 0.01) BUN than those on low energy intakes. J. WILDL. MANAGE. 39(4):692-698 For several years wildlife biologists have sought indices which would correlate well with the recent nutritional status of deer (Odocoileus spp.) and thus would be useful for evaluating trends in habitat conditions. Bone marrow fat, antler development, rumen content analysis, abomasal parasite counts, and many different hematological characteristics have been examined by various authors. None has proven entirely satisfactory, and it is anticipated that as deer management becomes more intensive the need for good indices of deer and habitat conditions will increase. Recent work on BUN in both domestic and wild species has indicated that this easily-measured characteristic might be of use as an index of recent nutritional status. Torell et al. (1974) and Blowey et al. (1973) have shown that BUN levels can be used as indicators of protein intake in domestic sheep and cattle, respectively. Seal et al. (1972b) suggested that BUN levels also might be useful as an index of recent nutritional status of pregnant white-tailed deer and presented limited data to substantiate this. Further, work by Seal et al. (1972a) on white-tailed deer and Franzmann (1972) on bighorn sheep (Ovis canadensis) has shown that BUN levels are not readily affected by the excitement of restraint or immobilization with certain drugs. The present study was conducted to investigate further the possible use of BUN as an indicator of recent nutritional status of deer. More specifically, the study was to determine the effect of known levels of energy and protein intake on BUN concentration 692 J. Wildl. Manage. 39(4):1975 This content downloaded from 157.55.39.179 on Tue, 12 Apr 2016 10:12:35 UTC All use subject to http://about.jstor.org/terms BLOOD UREA NITROGEN OF DEER FAWNS ? Kirkpatrick et al. 693 Table 1. Ingredient composition of pelleted experimental