Two experiments were carried out involving there dry and gestating Frisian cows in each one of them, to establish the voluntary comsumption of dry mater (CV), digestibility of dry matter (DMS), organic matter (MO), neutral detergent fibre (DNDF) and of the crude protein (DPB) of maize silage (MS) and of sorghum x Sudan pasture (SxS), with three levels of urea (0, 100 and 200 g/cow/day), both carried out in there periods of 15 days for each one of the they, according to a latin square model 3x3. The results showed that the addition of urea improves the CV, DMS, DNDF, DMO and DPB. The protein established proved positive with the addition of 200 g on both diets.