| Isaac M. Ortega, Sergio Soltero-Gardea, D. Lynn Drawe, and Fred C. Bryant |
| Authors are research associate, former graduate student, assistant director, and former professor, Department of Range, Wildlife, and Fisheries Management, Texas Tech University, Lubbock, Tex. 794092125 (IMO); Instituto Nacional de Investigaciones Forestales y Agropecuaries, Jalisco, Mexico (SSG); and Welder Wildlife Foundation, Sinton, Tex. (DLD), and Caesar Kleberg Wildlife Research Institute, TAMU-Kingsville, Kingsville, Tex. 78363 (FCB). |
Abstract |
| We studied cattle and deer diet quality within replicated grazing treatments of continuous and short-duration grazing at heavy and moderate stocking rates. The study was conducted at the Welder Wildlife Refuge, Sinton, Tex. from October 1987 to July 1989. We obtained cattle diet samples from esophageally fistulated steers. Deer diets were reconstructed using data obtained through the bite-count technique. Digestibility (IVDOM) and crude protein (CP) of cattle diets were similar between grazing systems and stocking rates. Digestibility of deer diets was affected by both grazing systems and stocking rates. Dietary CP and IVDOM of deer and cattle diets both differed among seasons. Dietary CP levels met maintenance requirements for deer throughout the study. Also, CP levels were high enough to meet low- to mid-gestation requirements. Deer dietary protein requirements for growth and lactation were never met regardless of grazing strategy. Although protein content of cattle diets was relatively low, these values satisfied cattle maintenance needs. Nursing cows, however, would not have met their requirement in any season sampled regardless of grazing system or stocking rate. Continuous grazing and moderate stocking rates may provide white-tailed deer the opportunity for selecting diets containing more desirable forbs and greater nutrient concentration. Less intensive rotational grazing at moderate rates may be preferred to maintain a relatively high seral stage. |
| Key Words: crude protein, IVDOM, digestibility, Coastal Bend of Texas, short-duration grazing, continuous grazing, Odocoileus virginianus |