In situ nitrogen degradability of concentrates in the rumen

Abstract

We measured the in situ nitrogen degradability of 125 samples corrresponding to 34 concentrate feeds. For a same cereal, the variations of grain degradability are low, but these of sub-products degradability (wheat bran and rice bran) are large and are depending of process. The heat treatment of concentrates involves always a significative decrease of degradability, whatever the concentrate and the process : extrusion of oilseeds and legume seeds, increase of cooking temperature of rapeseed, increase of dehydratation temperature of lucerne. The extent of decrease varies with the nature of feed and the conditions of treatment. In mean, the precision of in situ degradability measurement is 2.9 points, and its varies with the nature of feed, from 1 point for pea to 5 points for barley.