J.L. HOLECHEK, A.V. MUNSHIKPU, L. SAIWANA, G. NUNEZ-HERNANDEZ, R. VALDEZ, J. D. WALLACE and M. CARDENAS

New Mexico State University, Las Cruces, NM, USA

Abstract

In vivo digestibility trials were conducted to evaluate the influence of six shrubs common to the western United States, on intake and N retention by Angora goats. The six shrubs, alfalfa hay and blue grama hay were fed to goats in barley straw mixtures that contained between 7.7 % and 8.9% crude protein. High soluble phenolic/ tannin shrubs included honey mesquite (Prosopis glandulosa), creosotebush (Larrea tridentata), gray oak (Quercus grisea) and one-seed juniper (Juniperus monosperma). Low soluble phenolic/tannin species included common winterfat (Ceratoides lanata), fourwing saltbush (Atriplex canescens), alfalfa and blue grama. All diets resulted in a negative N balance. Creosotebush and gray oak diets had lower intakes and in vivo digestibilities than the alfalfa diet whereas common winterfat and fourwing saltbush gave a similar response to alfalfa. This study shows that high phenolic shrubs adversely influence goat nutritional status through reducing forage intake, digestibility and N retention. Because of this it is unlikely that goats would be effective in controlling these shrubs.