Two experiments were carried out to study the effect of moisture level and the addition of crude soya bean (HCS), as a source of ureases, on the effectiveness of the treatment or straw with urea. In the experiment 1, samples of 0.5 kg of wheal straw and barley straw were treated with urea at a dosage or 5% and final moistures contents of 20, 30 and 40%. The results showed that the increase of moisture level up to 30% caused a large decrease of neutral detergent fiber (NDF) content and an increase of in vitro dry matter digestibility (IVDMD), but the additional increment in moisture did not bring about further improvement. No differences were observed between the straws studied (barky vs wheat).
Experiment 2 was carried out on 5 stacks of approximately 300 Kg of barley straw. Four stacks were treated with urea solution at 4% on DM basis, at 15 and 25% of moisture level, and with or without addition of 3%, on DM basis, of HCS. One stack remained untreated. The higher moisture content and the addition of HCS increased the degree of ureolysis. Increasing moisture content from 15 to 25% improved the IVDMD value. However, the addition of HCS only had effect in treatments at 15% of moisture. Finally, all treatments improved the dry matter intake or straw, except when was carried out with 15% moisture and without addition of HCS.