Comparison of In vitro and In situ Techniques for Estimating Dry Matter Degradability in Some Feedstuffs

The objective of this study was to compare dry matter degradability of some feedstuffs including soybean meal, canola meal, barley grain, corn grain, alfalfa hay and corn silage by in vitro and in situ techniques. The in vitro method includes the ruminal digestion stage of the in vitro dry matter digestibility technique. Significant differences were observed between two methods in the estimation of the immediately soluble fraction for all feedstuffs except for canola meal (P<0.05). Two methods had significant differences with each other for estimating the potentially degradable fraction of soybean meal, barley grain, alfalfa hay and corn silage (P<0.05). It was not observed significant differences between two methods for estimating the degradability rate of the feedstuffs except for forage feeds. But, high correlations were observed between two methods in the estimation of the potentially degradable fraction (r=0.72), rate of degradability (r=0.89), potential of degradability (r=0.98) and the effective degradability (P<0.01). The results showed that there were significant differences between two methods in the estimation of degradability parameters, but the observed high correlation coefficients for some degradability parameters could indicate the relative ability of the innovative method.