PREDICTION OF BULK FODDER ORGANIC-MATTER DIGESTIBILITY BY THE ENZYME CELLULASE

Organic matter digestibility should be known for feed evaluation and d etermination of their nutritive value. OMD of grains is relatively con stant, but OMD of bulk fodder shows large variability of coefficients of digestibility depending upon the botanical species, growth stage an d degree of tissue lignification, harvest technology, preservation and storage, climatic and other factors. OM digestibility was determined by a two-stage in vitro method pepsin - cellulase in a set of bulk fod ders containing green fodder of clover and alfalfa (n = 22), green cor n (n = 8), silage of legumes (n = 7), rom silage (n = 18) and alfalfa hay (n = 21). Determinations followed the methods described by Jones, Hayward (1975), Vander Meer (1985) and Vencl (1990) with some modifica tions. In vivo OMD was determined in metabolism trials on wethers of t he Mutton Merino breed. Tab. I shows the size of tested samples, OMD v alues determined by the enzymatic method and in vivo OMD values of met abolism trials. The two-stage in vitro method pepsin - cellulase does not provide actual values in vivo. This fact is a reason for construct ion of regression equations of the relationship to the in vivo values obtained in metabolism trials. The relationship of enzymatically deter mined values to the in vivo values was expressed by calculation of the equations of linear regression and correlation coefficients (r) for t he particular groups of feeds. Tab. II shows the parameters of regress ion equations, correlation coefficients and value of residual standard deviations. The value of the correlation coefficients of the relation ship of OMD by cellulase to the in vivo values are high. The results o btained for clover and alfalfa, green com, com silage and alfalfa hay are statistically highly significant (P < 0.01).