Spanish Goat Diets on Mixed-brush land in the South Texas Plains

Microhistological analysis of feces from Spanish goats (Capra hircur) grazing in a mixed-brush complex in the South Texas Plains indicated that shrubs were their major foods during autumn, winter, and summer. Grasses were the major diet item during spring. Forbs, which were relatively scarce due to poor growing conditions during the U-month study, were of minor importance in goat diets. The importance in Spanish goat diets of several problem brush species, including blackbrush acacia (A cacia rigidula), condalias (Condalia spp.), guajillo (Acaeio bertimdieri), guayacan (Porliera angust~ofia), and wolfberry (Lycim berlandini) suggests a potential for utilizing these animals in conjunction with other brush management practices for more effective shrub control and for increasing efficiency of forage utilization on mixed-brush rangeland. The South Texas Plains are approximately 8 million ha which historically supported grassland or Savannah type vegetation (Thomas 1975). Long-term continuous grazing, periodic droughts, and the reduced frequency and intensity of fires have resulted in a Authors are research associate, professors, repectively with Texas Agricultural Experiment Station San Angelo 76901; and associate professor, Texas Agricultural Experiment Station, Uvalde 78801 This article is approved by the Director, Texas Agricultural Experiment Station as TA-18166. The authors express appreciation to Steve, Tom, and Mike Walker for providing land for this study, to P.H. Coates 111 for providing the goats, and to R.L. Potter for assistance with data analyses. This research was funded by the United States Agency for International Development Title XII Small Ruminants Collaborative Research Support Program under Grant No. AID/DSAN/XH-G-0049, in collabroation with Empress Braisileira de Pesquisa Agro-pccuaria; Brazil. Manuscript received November 18, 1982. 340 dense mixed-brush vegetation type in the central and western South Texas Plains, which is one of the most difficult-to-manage brush problems in the state. A variety of low-growing, xerophytic shrubs, including honey mesquite (Prosopis glandulosa Torr. var. glandulosa), acacias (Acacia spp.), condalias (Condafia spp.), spiny hackberry (Celtis pallida), cenizo (Leucophyllurn fnrtestens). agarito (Berberis trifoliolata), and cacti (Opuntia spp.) dominate typical South Texas mixed-brush communities (Scifres 1980). The increasing costs of herbicidal and mechanical brush control practices are forcing ranchers in the South Texas Plains to seek less expensive practices for management of mixed-brush rangeland. Goating has been used for many years in certain areas of Texas and the Southwest for control or suppression of undesirable brush (Vallentine 197 1, Merrill and Taylor 1976, Scifres 1980). The effectiveness of goating as a biological brush management practice depends on the size and species composition of the brush population, as well as on proper adjustment of stocking rate, duration, and frequency of grazing periods to intensity of the brush problem. Management of predators is usually necessary in areas where goats are grazed. Oates (1956) demonstrated that goats can kill certain brush species, such as Acacia spp. , without harming desirable forage plants. Goats can also effectively control or suppress oaks (Quercus spp.) and juniper (Juniperus spp.) (Magee 1957, Norris 1968). Merrill and Taylor (1976) reported that Spanish goats completely consumed new growth of shin oak (Q. mohriana), hackberry (Celtis reticulata), and pricklyash (Zanthoxylum sp.), while Angora JOURNAL OF RANGE MANAGEMENT 37(4). July 1984 goats (Capra hircus) utilized only about 30% of the shin oak and 80% of the hackberry and pricklyash. Warren et al. (1984) also found that Spanish goats consumed more browse than did Angora goats. However, they reported that neither Spanish goats, Angora goats, nor Rambouillet, Karakul, or Barbado sheep (Ovis aries) consumed appreciable quantities of the major undesirable brush species, including honey mesquite, creosotebush (Larrea tridenrata). tarbush (Flourensia ceruna), juniper, lotebush (Condalia obtusifolia), catclaw acacia (Acacia greggii). and agarita, on 3 study sites in western Texas. Goats feed over rugged terrain, and can be combined with other livestock to optimize utilization of vegetation (Campbell et al. 1962). Fraps and Cory (1940) concluded that goats, as compared to cattle or sheep, had a greater tendency to alter their diet with changing seasons and forage conditions. Addition of goats to grazing management systems in the South Texas Plains could substantially improve total forage utilization and diversify income sources for ranchers. Ideally, goats would suppress, as well as provide a means of marketing brush, and the improvement in range condition and sale of goat products would pay for predator control practices required for maintenance of the goat herd. We conducted a study during 1979-1980 to determine the extent to which Spanish goats graze the native shrubs on mixed-brush rangeland on the South Texas Plains.