Calcium kinetics in male white-tailed deer

Calcium kinetic analysis was combined with calcium balance data on two 2-year-old and two 4-year-old male white-tailed deer. There were three 10-day trials. Trial 1, February 3-13, was conducted after velvet shedding. Trial 2, May 26-June 5, was conducted after about a month of slow antler growth. Trial 3, August 18-28, was conducted shortly before velvet shedding, after the peak of antler growth. Significant differences (P less than 0.05) between trials 1 and 2 included increased calcium absorption and fractional calcium absorption from the intestine. Skeletal resorption decreased, resulting in an increased calcium balance. Significant differences (P less than 0.05) between trials 1 and 3 included increased skeletal accretion and total calcium flow into the pool. Nonsignificant differences (P greater than 0.05) between trials 2 and 3 included decreased average intestinal calcium absorption and increased skeletal resorption resulting in a decreased calcium balance. The younger deer had nonsignificantly lower (P greater than 0.1) endogenous fecal and significantly lower (P less than 0.1) urinary calcium excretions. The younger deer also maintained higher fractional absorption rates from the intestine than the older deer. The percent decrease in skeletal resorption and increase in calcium balance was greater in the younger deer between trials 1 and 2 and between trials 1 and 3.