Plasma Progestins and Puberty in Fawns as Influenced by Energy and Protein

Abstract

Captive female white-tailed deer fawns (Odocoileus virginianus) (24) were weaned at 3.5 mo. of age and randomly assigned to 1 of the following 4 treatments in a 2 .times. 2 factorial experiment: high energy-high protein, high energy-low protein, low energy-high protein and low energy-low protein. High and low energy diets averaged 3,064 and 2,498 kcal/kg, respectively. High and low protein diets averaged 18.2 and 9.6%, respectively. High energy diets caused a significant (P < 0.05) increase in progestin concentrations over low energy diets (0.75 vs. 0.32 ng/ml) when taken over the entire experiment. Nine of 11 animals on high energy diets and 0 of 8 on low energy diets had progestin levels of at least 1.00 ng/ml during the experimental period, probably indicating a higher incidence of ovulation and puberty in animals on high energy diets. Protein level had no appearent effect on progestin concentrations or attainment of puberty.