Determination of ruminal dry matter and crude protein degradability and degradation kinetics of several concentrate feed ingredients in cashmere goat

Abstract

The objective of this study was to determine the dry matter (DM) and crude protein (CP) degradation parameters of several commercially available concentrate feed ingredients used in Shaanbei White Cashmere Goat (SWCG). Three 4-year-old female SWCGs fitted with permanent rumen fistula were fed with corn straw and concentrate feed. Tested energy and protein feed ingredients were corn, wheat bran (WB), corn germ meal, soybean meal (SBM), rape seed meal (RSM), and distillers dried grains. The feed samples were placed in a nylon bag and incubated in the rumen for 0, 2, 6, 12, 24, 36, and 48 h to measure the ruminal disappearance of DM and CP. The exponential model was used to calculate the degradation kinetics. There were significant differences between sources in terms of DM and CP disappearance and degradability. In terms of energy feed ingredients, the potential degradability of DM and CP of corn was significantly higher than those of the other energy feed ingredients, whereas the effective degradability (ED) of CP of WB at three outflow rates was significantly higher than those of the others. In protein feed ingredients, SBM had the highest potential degradability of DM and CP. Furthermore, the ED of DM of SBM at three outflow rates was significantly higher than those of the other protein feed ingredients, whereas the ED of CP of RSM at three outflow rates was significantly higher than those of others. Those feed ingredients with low degradability can increase the bypass nutrients, which will be digested in the small intestine. The degradation parameters obtained in this experiment using SWCG would be useful in improving the accuracy of formulation of cashmere goat diet in Northwest of China.