Effect of silage additives on the intake and performance of male calves and steers

SUMMARY In two feeding experiments, an untreated silage which had received no additive was compared with silages which had received either formic acid (‘Add-F’) or a formalin and sulphuric acid mixture (‘Sylade’). The ‘Add-F’ was applied at the rate of 3·81/t and ‘Sylade’ at the rate of 3·1 1/t of fresh herbage harvested from a perennial ryegrass and white clover sward. The silages were offered ad libitum to 30 British Friesian male calves (mean fasted live weight 97 kg) in Experiment 1 and to 27 steers (mean fasted live weight 320 kg) of mixed breed in Experiment 2. Concentrate was offered to the animals in Experiment 1 at the rate of 0·86 kg dry matter/head per day. In each experiment the intakes of dry matter and digestible organic matter were higher from the additive-treated silages than from untreated silage. In Experiment 1 the application of ‘Sylade’ increased significantly (P < 0·05) the mean daily unfasted live-weight gain (0·87 kg/day) over that for animals offered untreated silage (0·74 kg/day). In Experiment 2 the mean daily unfasted live-weight gains from ‘Sylade’-treated (0·70 kg/day) and ‘Add-F’-treated silage (0·78 kg/day) were significantly higher (P<0·01) than that from untreated silage (0·38 kg/day).