No abstract

SUMMARYTwo groups of twelve-week-old Friesian steer calves were self-fed to a slaughter weight of 400 kg. on diets composed solely of either 85% rolled barley or ground maize and 15% of a supplement providing additionalprotein, calcium, phosphorus, iron, copper, cobalt, salt and vitamin A and vitamin D.There were no health problems on the barley diet, but five of the 15 cattle given maize died from bloat.Surviving animals on the maize diet took 344 days to reach a carcass weight of 231 kg.; comparable data for the barley-fed cattle were 362 days and 222 kg. The tenth rib cuts from the carcasses of cattle given maize contained significantly more fat and less water and ash than comparable cuts from the barley animals. Feed conversion ratio on the barley diet was 4·76.A comparison between the Friesian steers in the present trials and others given a lower energy diet containing ground roughage showed that with increasing concentration of the ration there was an increase in rate of gain, killing-out percentage and content of ether extract in the tenth rib cut.

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 48 Friesian steers given diets containing approximately 5, 20, 35 and 50% chopped barley straw and concentrates up to 100%. 2. Rates of live-weight gain between 130 and 400 kg declined from 1-18 to 0-65 kg/day and carcass gain declined from 0-62 to 0-30 kg/day as the straw content of the diet increased from 5 to 50%. 3. Alimentary tract 'fill' increased from 10-5% of live weight with 5% straw to 21% of live weight with 50% straw, and killing-out percentage dropped from 55-5% to 48-3%. 4. Both dry-matter digestibility and apparent nitrogen digestibility were lowest for the diet with 50% straw.

SUMMARY1. Seventeen Friesian steers, 25 Aberdeen-Angus crossbred steers and 33 Aberdeen-Angus crossbred heifers were fed on complete ground diets from 3 months of age until slaughter.2. The average time taken from 84 days of age to reach a slaughter live-weight of 400 kg. was 334 days for Friesian steers and 356 days for the crossbred steers. The crossbred heifers took 354 days to reach a slaughter live-weight of 350 kg. Feed conversion efficiency was best for Friesian steers and poorest for crossbred heifers.3. The ratio of hindquarter to forequarter in the carcass did not differ between breeds. There were marked differences in fat development, this being most pronounced in the crossbred heifers and least in the Friesian steers.4. The commercial value of the carcasses was assessed by a score card based on measurements, analysis of the tenth rib cut and visual appraisal. There was no difference between the scores for crossbred steers and heifers but the mean score for the Friesians was considerably lower.