Comparison between the Tilley-Terry and Pepsin-Cellulase Methods, used to Predict the Digestibility of some Minor By-Products in Ruminants

Ana Cișmileanu, Cătălin Dragomir, Smaranda Toma, Horia Grosu, Eugenia Mircea


While in vitro digestibility of the ruminants’ feeds is classically measured by Tilley-Terry (TT) method, more operative and simple enzymatic methods, such as pepsin-cellulase (PC) were alternatively developed. Use of PC was previously validated for the main groups of feeds, but less data are available for less known, “minor†by-products. The aim of this experiment was to assess the correlation between the digestibility of some minor by-products sampled from the Romanian feed market (winery by-products, protein meals), estimated both by TT and PC methods. The results revealed a very high similarity between the digestibility data obtained by this two methods (R squared=0.9648 and RSD=4.229).The conclusion is that PC method can reasonably replace the Tilley-Terry method to determine the total tract digestibility of minor by-products.


digestibility; pepsin-cellulase method; ruminants

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