EVALUATION DE LA DEGRADATION DE LA MATIERE SECHE DES FOURRAGES DANS LE RUMEN DES BOVINS ET DES OVINS PAR LA METHODE DES SACHETS DE NYLON

Abstract

Rumen degradation of dry matter (DM) from different cultivars of timothy and bromegrass cut at two stages of maturity was determined by the nylon bag technique using one cow and five sheep. There were no significant differences in the DM degradation of the cultivars tested within each stage of maturity regardless of the animal species used. However, DM degradation was greater at the heading stage of maturity than at full bloom (P < 0.05). Absolute values for DM degradation were always higher for the cow than for sheep (P < 0.05). There was a linear relationship between DM degradation coefficients for the cow and the sheep. Between the values of 55 and 70% of DM degradation, one unit increase in DM degradation of forages in the sheep corresponded to a similar increase in the cow. Therefore, within these limits we can extrapolate from one species to the other when using the nylon bag technique. With feedstuffs presenting higher or lower DM degradation coefficients than within the range of 55–70%, extrapolation between species would not be recommended because of species differences in the utilisation of feedstuffs. Key words: Forages, nylon bags, ruminants