Beef production from silage 2. The performance of beef cattle given silages of either perennial ryegrass or red clover

Abstract

ABSTRACT1. A primary growth of perennial ryegrass was cut on 8 to 11 May (early) or on 12 June (late) for comparison with the primary growth of a tetraploid red clover, which was cut either on 1 or 2 June (early) or on 28 June (late). The crops were ensiled, after wilting for about 4h, with the addition of formic acid at 2·21/t fresh crop. The silages were given ad libitum alone or with rolled barley at 11·5 g dry matter per kg live weight to 40 British Friesian steers initially 3 months old and 108 kg live weight.2. On average there was no significant difference in digestibility between perennial ryegrass and red clover. However, the rate of decline in digestibility with time was greater with perennial ryegrass than with red clover.3. Calves given silage of red clover as the sole feed ate more dry matter and grew faster than calves given grass silage (P <0·001) but supplementation with barley reduced the intake of red clover silage to a greater extent than that of perennial ryegrass silage. Barley supplementation increased live-weight gain of calves given perennial ryegrass from 0·32 to 0·83 kg/day and that of calves given red clover from 0·63 to 0·99 kg/day (interaction P <0·05). The results did not indicate a higher net efficiency of utilization of the legume. Date of cut had no significant effect on dry-matter intake but earlier cutting resulted in an increase in live-weight gain from a mean of 0·61 to 0·77 kg/day (P <0·001).4. The results show that high rates of live-weight gain (0·74 kg/day) can be achieved by calves given silage of red clover and that earlier cutting of herbage for silage does not always result in higher intakes of dry matter. Supplementation of silages with barley can reduce markedly the difference in intake and live-weight gain apparent when the silages are given as sole feeds.