Intensive beef production 13. Replacement of concentrates with root crops

Abstract

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.

Free-choice feeding of cattle on swedes and grass silage

“…Macdearmid, personal communication), while other work (with entire male Friesians of 220 kg live weight) suggests that maximal intake was reached after 7 weeks when swedes provided 50% of DMI (McKelvie, Olorunda and Kay, 1975) or 10 weeks when swedes alone were given to Friesian steers weighing less than 350 kg (Kay et al, 1972). Entire male Friesians (180 kg live weight) fed on swedes alone reached only 65 % of their maximum intake after 28 days on trial (A.…”

“…Swedes (Brassica napus) are widely utilized in north-east Scotland and the substitution of rolled barley by swedes had been examined in a number of trials (Kay, Macdearmid and Massie, 1972;Latif, 1977;0rskov, Andrews and Gill, 1969). Root crops may replace concentrates, either wholly or in part.…”