Effects of winter undernutrition on body composition and physiological profiles of white-tailed deer

We examined the effects of undernutrition and recovery on body composition and blood and urinary profiles of 6 captive white-tailed deer (Odocoileus virginianus) between 18 December 1984 and 3 May 1985. Deer were weighed, and blood and urine were collected every 2 weeks from 10 January to 3 May. At Weeks 2, 8, and 14, body composition was estimated by the dilution of tritiated water technique and standard predictive equations. Feed intake decreased and cumulative mass loss increased during nutritional restriction. Baseline body composition included 62.1 .+-. 0.9 (SE)% water, 11.9 .+-. 1.0% fat, 20.5 .+-. 0.7% protein, and 4.5 .+-. 0.0% ash. Percent protein loss was linearly related (r2 = 0.91, P < 0.001) to percent mass loss. Peak mass loss from the beginning of the study (12.8 .+-. 2.0%) occurred at Week 12; estimated protein loss was 12.5%. Fat reserves were 85% depleted from Week 2 to Week 14. Elevated packed cell volume (PCV), serum calcium (Ca), cholesterol, triglycerides, and cortisol; and diminished serum urea nitrogen, thyroxine (T4), urinary urea nitrogen:creatinine and potassium:creatinine were associated with reduced food intake, mass loss, and decreases in body water, fat, and protein. Altered values of most of these blood and urinary characteristics reflected initiation of nutritional recovery after nutrition improved. Sequential data collection and the use of a combination of indices in blood or urine will yield the most useful assessments of animal nutrition and condition.