Dietary Supplementation Strategies for the Captive White-tailed (Odocoileus virginianus) Breeding Doe

Captive breeding and hunting of white-tailed deer in Texas is a popular business enterprise with significant economic impact. Stress in captive white-tailed breeding does may compromise their performance, alter immunity and increase death loss. Major stressors in captive deer include handling, weather extremes and poor nutrition. To alleviate stressors and the associated reduced performance cost to owners and breeders, it is necessary to research non-invasive methods to improve deer performance. Such methods may be dietary inclusion of feed additives comprising probiotic or plant-based essential oils, or dietary inclusion of a supplement known to have immunomodulatory effects in other species. Two experiments were performed to test these methods. Experiment 1 was conducted from 15DEC2015 to 8MAR2016 at a private deer breeding facility near Canadian, TX and does (n = 71) were weighed, palpated and blood sampled on d 0, 42 and 84 to determine weight maintenance, rib flesh score (RFS) and complete blood count via automated hemocytometer, respectively. Deer were randomly allocated to 1 of 6 treatment pens according to pre-assigned chute entry order. The two treatment diets consisted of a commercial deer breeder diet with no additive (CON) or the same breeder diet with a dietary immunomodulator (OmniGen-AF, Phibro Animal Health) included at 3.51 g/kg of feed (OG). Treatment diets were supplied via self-feeders located in each pen. The OG does lost less (P = 0.45) weight, numerically, throughout the study and tended (P = 0.10) to consume less feed; indicating that the OG does had increased feed efficiency compared to does consuming the CON treatment. Further, OG-treated does tended to have a greater (P = 0.09) RFS on d 42. There were no treatment differences for CBC variables (P ≥ 0.32); however, total leukocytes, neutrophils and neutrophil: lymphocyte decreased with time (day effect, P ≤ 0.02). These CBC data may provide a foundation for automated CBC reference range in captive white-tailed does. Experiment 2 was conducted from 23Jun2016 to 15Sep2016 at the same study site using the same experimental methods as Exp. 1 except blood was not collected. The two treatment diets consisted of a complete feed without additive (CON) and the same breeder diet with a phytogenic nutritional supplement included (CG; Climate Guard, Delacon). From d 0 to 84 there was not a difference (P ≥ 0.19) in ADG or BW gain, but numerically, CG does weighed more and CG-treated does gained BW; whereas, CON lost BW during the 84-d trial. There was a tendency (P = 0.06) for RFS to be greater in CG-treated does on d 42, and a difference existed (P < 0.01) by d 84 for CG to have greater RFS. Overall, breeding does receiving the phytogenic nutritional supplement in their diet consumed more feed, gained BW and exhibited increased RFS during the 84-day observation period. Results of these experiments indicate that nutritional supplements may improve performance in captive deer, but further research is needed to determine the most effective supplement type during different seasons and their impact on stress.