Sand Shinnery Oak as Forage for Angora and Spanish Goats

Abstract

Little information is available on goat nutrition and diet selection on shrub-dominated ranges. This study examined the botanical and nutritive composition of Angora and Spanish goat diets, and forage intake when grazing on sand shinnery oak (Quercus havardii Rydb.) range in west Texas during June, July, and August, 1986. A digestion trial evaluated the nutritive value of shinnery oak diets for goats. Angora and Spanish goats consumed similar amounts of shinnery oak, grass, and forbs. Their diets had similar levels of crude protein (CP), fiber, and in vitro digestibility. Consumption of oak by goats increased from 31% of diets in June to 55% in August. Dietary CP levels averaged 8.1 to 9.4% during the summer. In vitro digestibility of diets varied from 44 to 53% during the summer, with lower values during July and August. Spanish goats had higher forage intakes during July and August compared to Angora goats. Digestible energy (DE) intake (Mcal/-day) did not differ between breeds, but increased during the summer. The digestion trial was conducted using 0, 25, and 50% shinnery oak with alfalfa hay. Apparent organic matter digestibility (OMD) declined linearly with increasing levels of oak; the same decline was noted for apparent CP and neutral detergent, but not acid detergent, fiber digestibility. Extrapolated OM and CP digestibilities for 100% oak were 38% and 17%, respectively. Voluntary OM intake did not differ among diets. CP and DE intakes declined linearly as dietary oak levels increased. Fecal N increased and urinary N decreased linearly with increasing levels of oak in diets. We found no evidence of intoxication from shinnery oak in grazing or pen-fed goats. Shinnery oak can contribute substantially to the nutrition of goats foraging on these ranges, but some supplemental feeding may be necessary.