The effect of animal species on in sacco degradation of dry matter and protein of feeds in the rumen

A study was undertaken on lucerne (LUC), ryegrass (RG), kikuyu (KIK), soybean meal (SBM), wheat grain (WG) and meat and bone meal (MBM) to determine the effect of animal species (sheep versus cattle) on in sacco degradation of dry matter (DM) and protein. The approach of cubic smoothing splines ®tted as a linear mixed model was used for the analysis of degradability of DM and protein of feeds. The quickly degradable DM (QDDM), cumulative slowly degradable DM (CSDDM), total degradable DM (TDDM) and rate of degradation of slowly degradable DM of LUC, RG, KIK, SBM and WG in the rumen of sheep and cattle were not different (p > 0.05). The QDDM, CSDDM and TDDM of these forages and concentrates ranged from 22.9 to 57.6, 35.3 to 54.9 and 70.2 to 92.9 (g/100 g). Estimates of in sacco quickly degradable protein (QDP), cumulative slowly degradable protein (CSDP), total degradable protein (TDP), rate of degradation of slowly degradable protein of LUC, RG, KIK and SBM were similar (p > 0.05) for sheep and cattle. For the WG a vertical shift was found in the species cubic splines ®tted to logit transformed protein degradation data. This resulted in QDP of 52.0 and 43.8 g/100 g, CSDP of 41.6 and 48.0 g/100 g and TDP of 93.6 and 91.6 g/100 g for sheep and cattle, respectively. In sacco degradation of DM and protein of MBM was irregular for both sheep and cattle, consistent with extreme heterogeneity of the concentrate. # 2000 Elsevier Science B.V. All rights reserved.