Development of Lure Forages for Minimizing Winter Depredation By Deer in South Dakota

Abstract

Despite the number of deer (2-31/km2) that inhabit South Dakota, little is known about their growth rates or nutritional requirements and characteristics during severe winters. The objectives for this study were: 1) To document and compare growth rates of fawns from eastern South Dakota and the Black Hills; 2) To develop/evaluate feeds (lure forages) for deterring deer from depredating stored feed sources in South Dakota; and 3) To evaluate physiological and nutritional condition of captive deer maintained on lure forages. Growth rates of captive South Dakota deer were documented from spring 1997 through 1999. Twenty-one white-tailed deer (Odocoi/eus virginianus) fawns that had been abandoned and were turned over to the South Dakota Department of Game Fish and Parks were obtained and raised over a 2-year period. Eleven fawns were obtained from the Black Hills region of South Dakota; 10 fawns were obtained from the eastern portion of the state (east of the Missouri River). Daily growth rates (pre-weaning) of fawns averaged 0.16 � 0.008 [SE] kg. Relative to overall growth rates of white-tailed deer, no difference (P \u3e 0.05) was associated with sex. A significant interaction occurred between year and location (P = 0.019) for fawn weights. At 1 year-of-age a difference in fawn weights was associated with sex (P = 0.014) and location (P = 0.0009). During winter months of 1997-98. 1998-99, and 1999-2000 deer were randomly placed into diet trials. Eight experimental diets/feeds were formulated and fed to captive deer. Diets used in trials were: shelled corn (diet 1 ), a 16% Crude Protein (CP) pelleted ration (diet 2), a 14% CP pelleted ration (diet 3), alfalfa hay (diet 4), pelleted soy hulls (diet 5), pelleted soy hulls combined with shelled corn (diet 6), pelleted soy hulls combined with alfalfa hay (diet 7), and combinations of diets 1, 2, and 4 (diet 8). Nutritional condition of deer was evaluated by monitoring body weights and blood serum metabolites (i.e., glucose [Wesson et al. 1979], blood urea nitrogen [Kirkpatrick et al. 19751), and blood pH (Essig et al. 1988). Blood serum metabolites were chosen to indicate: acidic levels (pH), stress (Cortisol). Dietary protein (Blood Urea Nitrogen [BUN]), and available energy (Glucose). Overall blood parameters did not differ pre-trial (P = 0.114). However, BUN levels posttrial (P \u3c 0.001) differed significantly. Passage rate trials were conducted each winter. Total mean retention time (TMRT) of experimental forages did not differ (F = 0.513, df = 6,25, P = 0.793). Cafeteria trials were conducted January of 2000. Corn was the preferred diet followed by pelleted soy hulls, and alfalfa hay. The 16% pelleted diet appeared to be the least preferred. It is recommended that pelleted soy hulls could be used as a lure forage, provided there is some roughage available to the herd in question