In situ and in vitro degradation of native Texas warm-season legumes and alfalfa in goats and steers fed a sorghum-sudan basal diet

The objective was to determine in situ degradation (ISD) rates of herbaceous native Texas legumes when incubated in ruminally fistulated goats and cattle fed a basal diet of sorghum-sudan hay (643.7 ± 75.1 g/kg neutral detergent fiber (NDFom), 77.3 ± 20.5 g/kg crude protein (CP)). Velvet bundle flower (Desmanthus velutinus) (414.7 ± 14.9 g/kg NDFom, 184.9 ± 11.2 g/kg CP), prairie acacia (Acacia angustissima var. hirta) (340.9 ± 36.5 g/kg NDFom, 186.5 ± 46.7 g/kg CP), tropical neptunia (Neptunia pubescens) (387.3 ± 3.0 g/kg NDFom, 169.8 ± 12.2 g/kg CP) and alfalfa (Medicago sativa) (498.0 ± 8.0 g/kg NDFom, 197.9 ± 2.8 g/kg CP) were incubated in situ for 0, 4, 8, 16, 24, 48 and 96 h. There was no interaction between animal species and forage for dry matter (DM) or organic matter (OM) ISD. Because animal species did not affect most ISD parameters, data was pooled between species. The greatest rate of ISD was in alfalfa and, among the native legumes, A. angustissima var. hirta and N. pubescens contained a greater amount of soluble and slowly degraded DM and OM than D. velutinus indicating that they possess greater potential nutritive value under these conditions.