Published online by Cambridge University Press: 02 September 2010
1. Fifty-four weaned single-suckled steer calves aged 11 to 14 mo were individually fed 2 kg wet distiller's grains, 10 kg swedes and an average of 11·5 kg grass silage daily. The quantity of silage offered was adjusted during the experiment in accordance with a live weight related scale. There were six treatments differing in the physical form, moisture content and level of barley grain offered. A nil barley supplement was compared with 2·5 kg barley dry matter daily offered either whole or bruised having been prepared for storage by drying (84·6% DM) and by treatment with propionic acid (79·9% DM); dried barley was also offered whole (at approximately 50% DM) after soaking in water for 24 hr. Each replicate of six cattle, one animal from each treatment, was slaughtered when all its members were subjectively estimated to have the required minimum body condition and minimum estimated carcass weight (186 kg) for marketing.
2. A supplement of barley grain caused increases in daily live-weight gain, slaughter weight, carcass weight and carcass fat content; and reduced carcass lean and bone content. These effects were increased if the barley grain was processed by bruising compared to being consumed unprocessed (whole). There was no indication that the method of preparation for storage or the moisture content of the barley grain when consumed affected the results of the experiment. It was concluded that the costs of processing barley grain by bruising for feeding to growing cattle for slaughter will be exceeded by the value of the additional animal performance obtained in comparison to feeding whole barley grain.