Comparison of organic matter digestibility determined by in vivo and in vitro methods

A total of 36 samples of feed - 19 samples of hays and 17 samples of silages were used for estimation of in vivo and in vitro digestibility. The organic matter digestibility (OMD) was estimated by in vivo and two in vitro techniques (method of Tilley and Terry and two-stage pepsin-cellulase method (Pepcel)), The regression equations were calculated from the results obtained in the experiment. Tilley and Terry method provided consistent results of OMD estimation for both the groups of roughages: in vivo OMD = 14.7 + 0.782 x [Tilley and Terry] (n = 18; R-2 = 0.76); in vivo OMD = 36.3 + 0.513 x [Tilley and Terry] (n = 16; R-2 = 0.75) for hays and silages, respectively. Different accuracy was found out in Pepcel method: in vivo OMD = 37.0 + 0.478 x [Pepcel] (n = 19; R-2 = 0.49); in vivo OMD = 37.8 + 0.484 x [Pepcel] (n = 17; R-2 = 0.87) for hays and silages, respectively.