Estimating Seasonal Diet Quality of Pronghorn Antelope from Fecal Analysis

Abstract

Botanical composition of pronghorn antelope diets from fecal analysis and nutrient quality of samples of plants known to be used by pronghorn were evaluated from June 1979 to May 1980 in Oldham and Hartley counties of the Texas Panhandle. Pronghom in this area consume forbs primarily throughout the year, followed by browse and grasses. Pronghom exhibited an affinity for either Artemisia ludoviciana or Sphaeralcea coccinea, or both, in all seasons. Grass use was negligible. Seasonal crude protein estimates ranged from a low of 9.8% in winter to a high of 11.4% in spring. Estimates of phosphorus were loweffin winter (O.l5%)and highest in spring (0.18%) corresponding fr approaching 2,227 kcal/kg, and highest in spring and summer, 2,656 and 2,631 kcal/kg, respectively. Average in vitro digestible organic matter coefftcients for spring, summer, fall, and winter were 69%, 67%, 53%, and 6195, respectively. The combination of fecal analysis for botanical composition and nutrient content from samples of plants known to be ingested provides at least an estimate of nutrient content of the diet. Evaluating the quality of a habitat for ungulates requires estimates of nutrient supply from the vegetation complex. For freeranging wild ungulates like pronghorn antelope (~nrrrocu~ru americana), gross estimates must sometimes be substituted where use of refined techniques are limited. Chemical analyses of plants collected from uneaten forage usually accompany some estimate of the diet. Smith and Malechek (1974) estimated pronghorn diets At the time of this research, the authors were research assistants and Bryant was assistant professor, Department of Range and Wildlife Management, Texas Tech University, Lubbock. Koerth is currently research associate, Texas Agricultural Experiment Station, Rt. 2, Box 589, Corpus Christi, Tex. 78410. Krysl is now with Range and Animal Science Department, New Mexico State University, Las Cruces, 88001; Sowell is with Dept. Range Sci., University of Wyoming, Laramie, 82071. Partial funding of this project was provided by the USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Great Plains Wildlife Research Laboratory, Lubbock, Texas, the Ceasar Kleburg Foundation for Wildlife Conserva!ion, an! the Noxious Brush and Weed Control Program, Texas Tech University. This 1s TechnIcal Article T-9-275, College of Agricultural Sciences, Texas Tech University. Manuscript accepted April 27, 1984. 560 using ocular estimates of forage removed by free-ranging pronghorns and subsequently hand-picked samples and composited by weight those plants consumed for later chemical analyses. Schwartz et al. (1977) hand-picked plant samples to duplicate observations of tame pronghorn and attempted to estimate dietary nutritional content from mean bite-weight. The objective of this study was to evaluate nutrient content of pronghorn diets from known botanical diet composition using fecal analyses, and nutrient consumption of herbages determined from hand-harvested samples.