Nutrient digestion and nitrogen utilization by goats fed native shrubs Celtis pallida, Leucophyllum texanum and Porlieria angustifolia

An in vivo digestibility trial was conducted to evaluate the influence of shrub leaves on digestion and N retention by goats. Twelve male castrated Spanish goats (33.1 +/- 2.4 kg BW) were randomly placed in metabolism stalls and assigned to three diets (four goats/diet): (1 control) 23% alfalfa hay plus 77% bean straw (BS), (2) 22% hackberry (Celtis pallida) plus 78% BS and (3) 18% ceniso (Leucophyllum texanum) plus 18% soapbrush (Porlieria angustifolia) plus 64% BS. All diets contained 1.5% N. Diets were offered in two equal portions daily. The DM and CP intakes of goats were similar (P > 0.05) among diets. However, NDF and ADF intakes were lower (P < 0.05) in goats fed diets with hackberry and ceniso plus soapbrush than goats fed alfalfa hay. Digestibilities of DM and CP were similar (P > 0.05) among goats. Cell wall and its fractions were digested less efficiently (P < 0.05) when goats were fed the hackberry and ceniso plus soapbrush diets instead the alfalfa hay diet. Goats retained N in a manner similar (P > 0.05) among diets. Differences on fiber digestion between diets containing alfalfa hay and browse species may be related to the chemical or physical nature of the cell wall. (C) 1998 Elsevier Science B.V.