Milk production from silage 3. A comparison of red clover with grass silage

Abstract

Silages were made from the primary growth of perennial ryegrass (Lolium perenne) or red clover (Trifolium pratense) and were given ad libitum to 52 British Friesian cows, together with 70 kg dry matter per day of a barley/ground maize/soya bean supplement in 2 years. Twenty of the cows were used in both years, providing a total of 72 observations. Three treatments were imposed during weeks 3 t o 20 of lactation: red clover silage, (RC/RC); red clover silage, weeks 3 to 10, grass silage weeks 12 to 20 (RC/PRG); grass silage (PRG/PRG).Apparent digestibility of the gross energy assessed in lactation weeks 14 and 15 was slightly lower for red clover than for perennial ryegrass (0·683, 0·706 and 0·701 for treatments RC/RC, RC/PRG and PRG/PRG respectively). There was no effect of previous treatment on the digestibility of perennial ryegrass diets (RC/PRG v. PRG/PRG). Cows given red clover silage consumed proportionately 1·22 of the dry matter and 1·09 of the digestible energy ingested by those given perennial ryegrass. The intake of perennial ryegrass in mid lactation was similar, irrespective of early lactation treatment.During weeks 3 to 20, cows given red clover yielded 1·9 kg more milk than did those given perennial ryegrass (P < 0·01). However, this milk had a significantly lower concentration of fat (P < 0·01; 37·2 and 41·2 g/kg for treatment RC/RC and PRG/PRG respectively). In mid lactation the cows that had received red clover silage in early lactation (RC/PRG) had the lowest yield of milk, milk fat, protein and lactose and the difference between this treatment and PRG/PRG was significant for milk and milk fat yields (P < 0·05).Red clover silage rather than perennial ryegrass silage of similar digestibility resulted in higher silage intake and higher yields of milk, milk protein and lactose. However, the strategic use of red clover silage to increase yield in early lactation did not induce positive residual effects in mid lactation; rather, there was evidence of a negative effect on milk and milk-fat yield.