Centro Dominicano de Investigación Pecuaria can Caña de Azúcar CEAGANA, Santo Domingo, Republica Dominicana

Zebu bulls fed ad libitum liquid molasses and urea were given cassava forage as a combined source of protein and roughage at the level of 3% of live weight (fresh basis) daily. On one treatment the cassava forage was broken into fairly long pieces (about 30 cm) while on the other it was passed through a stationary forage chopper to give particles of about 3 cm. The forage was given once daily in the morning. During the first 56 days of the trial growth was poor for both treatments (110 and 50 g/d for coarse and fine processing) but increased significantly(P <.001) to 580 and 660 g/d during the final 64 days of the experiment. Rumen samples taken at the end of the second phase of the experiment showed the characteristic pattern for molasses-based diets with relatively high proportions of butyrate (30% molar) and low proportions of propionate (12%), The effect of giving the forage was to increase the molar proportion of acetate and decrease that of butyrate with no consistent effect on propionate. It could not be determined if the apparently long period of adaptation, represented adaptation to the molasses or to the cassava forage.