Effect of Water Restriction on Feed Intake of White-Tailed Deer

Abstract

We offered 9 male white-tailed deer (Odocoileus virginianus) feed and water ad libitum for 34 days, and measured intake of both daily. We provided separate groups (3 x 3 balanced, simple crossover design) 33, 67, and 100% of ad libitum water intake for 4 days. Mean dry-matter intake (DMI) (g/kg body wt [BW]VP.7) for 3-4 days prerestriction was compared to each of the 4 days on restriction. Dry matter intake decreased (P < 0.01) for deer receiving 33% of ad libitum water intake on days 3 and 4. One deer refused feed on day 4. There was a difference (P < 0.05) in mean DMI on day 3 between the group receiving 100% of ad libitum water and the group that received 33% of ad libitum water. Differences in DMI existed on day 4 among all 3 groups (P < 0.05). The group receiving 33% of ad libitum water lost more weight than the other groups (P < 0.05). Because of lower than expected BW losses by the water-restricted animals, it appears that white-tailed deer possess some degree of physiological adaptation to dehydration. High daily maximum temperatures (36 C) may have exacerbated the effect of water restriction on DMI. Because of high temperatures and frequent summer droughts in southern Texas, the need for adequate water for whitetailed deer may be critical. J. WILDL. MANAGE. 52(4):602-606 Knowledge of the role of water in deer physiology and ecology in hot, arid environments is limited. Experimental studies examining the role of water in deer physiology are limited, and most work has addressed ad libitum water intake or distribution and habitat preferences of deer in relation to water (Elder 1954, Welch 1960, Michael 1968, Longhurst et al. 1970, Hervert and Krausman 1986). The need for supplemental water may be especially important in southern Texas because prolonged periods of high temperature and drought are common (Norwine and Bingham 1986, Rappole et al. 1986). Understanding water needs of deer could help explain their productivity, forage selection, and activity patterns. Robbins (1983:24) noted that wildlife biologists have often used water development without adequate understanding of the importance of water to target species. We report the effect of water restriction on feed intake of white-tailed deer in a hot environment. We thank A. Aguilar, L. G. Arguelles, and D. A. Boyer for assistance with animal handling; R. L. Bingham and N. E. Koerth for assistance with statistical analyses; and J. H. Rappole and F. S. Guthery for review of this manuscript. This project was partially funded by National Institute of Health Grant 506-RR-08107.