Relationship between the physical parameters, chemical compositions and rumen degradation kinetics parameters of certain feedstuffs for ruminants

Abstract

The primary objective was to investigate the relationship between the physical parameters, nutrient components, and degradation characteristics of feedstuffs. Thirteen kinds of feedstuff were selected to analyze the physical properties (including water holding capacity (WHC), swelling, bulk density, and feed solubility), chemical compositions and degradation parameters. The results showed that these parameters were widely altered among the feedstuff varieties. Correlation analysis indicated that WHC was negatively correlated with the contents of starch, crude protein (CP) and ether extract (EE). However, WHC had a highly positive correlation with the cell wall content parameters. Swelling had a high negative correlation with starch and EE, and had a positive correlation with ash. Bulk density was negatively correlated with neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL). DMSol (%DM) was negatively correlated with NDF, ADF and ADL, but highly positive correlated with CP content (rSpearman=0.77, P<0.0001). Additionally, there was a positive association between the effective degradability of DM (EDDM) and bulk density (P<0.05) and DMsol (P=0.001). Also, the effective degradability of CP (EDCP) was negatively correlated with WHC (rSpearman=−0.46; P=0.003) and positively correlated with DMSol (rSpearman=0.503; P=0.001). A stepwise linear regression analysis indicated that NDF, ADF and CP could be predictors of WHC, bulk density and DMSol, respectively. In conclusion, the physical properties can be taken as important evaluation indices, which might be potentially used to estimate the nutritive values of the feedstuffs and can also be applied in a ration formulation.