Four rumen-cannulated steers were fed a diet consisting of whole maize grain, high protein concentrate and molasses. Two of the four animals received 10% ground Eragrostis curvula hay in addition to the whole maize grain diet. The feeding period was divided into four periods of 11 days to determine the effect of adaptation on digestibility. In a further final period of 11 days, the diets were fed manually via cannulae to avoid initial mastication of the grain. For the animals receiving no roughage, the in vivo dry matter digestibility values for the five periods were as follows: 83,7; 84,4; 81,8; 80,0 and 81,4%, whereas for animals receiving additional roughage, corresponding values were 73,7; 71,8; 70,2; 71,6 and 67,7%.