INFLUENCE OF FORBS AND SHRUBS ON INTAKE, DIGESTIBILITY, AND NITROGEN AND ENERGY-BALANCE IN SHEEP FED LOW-QUALITY STRAW

A 4 X 4 Latin square experiment (Exp) was conducted using eight Deboui llet yearling wethers with two wethers/cell to compare the effects of forbs and shrubs supplementation to a low-quality barley straw with al falfa hay (ALF) supplementation in terms of nutrient digestion and bal ance. Diets studied in the Exp were barley straw (0.56% N) and straw p lus either 42% ALF, 63% forbs (a 50:50 mixture of scarlet globemallow and leatherleaf croton) or 62% shrubs (mixture of 50% fourwing saltbus h and 50% mountain mahogany). Diets containing ALF, forbs and shrubs w ere isonitrogenous (1.68% N). Periods of each Latin square were 15 day s with total fecal and urine collections obtained on the last 5 days o f each period. Dry matter intake of ALF and shrub-containing diets was similar and higher (P < 0.05) than straw alone or straw plus forb die ts. Nitrogen (N) retention was improved, but NDF digestibility was red uced (P < 0.05), in diets containing ALF and shrubs compared with stra w only. No difference in N retention among diets were detected (P > 0. 05) when N intake was used as a covariate. Metabolizable energy (ME) c ontent of all the diets was similar except the shrub containing diet t hat was lower than the straw plus forbs or straw plus ALF but similar to the straw diet. Forbs had little influence on digestion and N utili zation in the Exp presumably because of their reduced acceptability in the dried and ground form by sheep. Results suggest that native shrub s used in the study influenced intake and N utilization in a manner si milar to ALF; and forbs used were similar in ME to ALF.