[Effects of the addition of iso-acids to feed on ruminal fermentation, in sacco degradation of dry matter and the concentration of several blood parameters in cows].

Three rumen-fistulated cows fed maize silage and concentrates were supplemented with either soybean oil meal or urea, associated or not with isoacids. The isoacids increased the volatile fatty acid concentration, lowered the ruminal ammonia concentration and in sacco dry matter disappearance and did not influence blood parameters.