1. A growth trial was carried out with 21 Friesian steers given diets containing either 0%, 30% or 50% ground straw, and concentrates up to 100%. 2. Steers offered the diet containing 0% straw consumed less dry matter per day than steers on the other two treatments. 3. Rates of live-weight gain were 1-20, 1*04 and 0-87 kg/day for the three treatments respectively, and carcass gains were 690, 550 and 440 g/day. 4. Killing-out percentage dropped and alimentary-tract fill increased as the proportion of straw in the diet increased. 5. The dry-matter digestibility coefficients for the three diets, determined at maximal intake, were 79*1 %, 62-3 % and 56*6 %, respectively.

1. Two growth trials and a digestibility trial were carried out with a total of 84 British Friesian steers to investigate the substitution of root crops for a part of the concentrates in an all-concentrate diet. In Trial 1 six experimental diets were offered ad libitum and contained, on a dry-matter basis, (1) 100% concentrates, (2) 34%, (3) 66%, (4) 87% sliced swedes and (5) 66%, (6) 87% whole potatoes. In Trial 2, five diets were offered ad libitum and contained (1) 100% concentrates or (2) 34%, (3) 50%, (4) 66%, (5) 100% swedes. 2. In both the growth trials when the steers weighed less than 350 kg live weight, daily dry-matter intake was lower for steers offered the highest proportion of swedes than for steers offered concentrates. Substitution of potatoes for concentrates resulted in a higher daily dry-matter intake and daily live-weight gain than did substitution of swedes. 3. In Trials 1 and 2 rate of live-weight gain and in Trial 2 carcass gain were similar for steers on treatments 1 and 2. In Trial 2 liveweight gain declined from 1-05 to 0-87 kg/day and carcass gain declined from 0-62 to 0-51 kg/day between steers on treatments 1 and 5. 4. The replacement of concentrates with swedes or potatoes did not affect the overall digestibility of dry matter.

SUMMARY1. A growth trial was carried out using 24 British Friesian steers given diets containing (1) 100%, (2) 60%, (3) 40% and (4) 0% concentrates and chopped dried grass up to 100%.2. Daily dry-matter intake was significantly lower for steers on Treatment 1 than for steers on the other three treatments.3. Rate of live-weight gain declined from 1·18 to 0·88 kg/day and carcass gain from 625 to 430 g/day between steers on Treatments 1 and 4.4. Killing-out percentage dropped from 55·3% (1) to 51·9% (4) and the 8th-10th rib from steers on Treatments 3 and 4 contained significantly more crude protein and less ether-extractable matter than ribs from steers on Treatments 1 and 2.