Evaluation of formic acid as an additive for lucerne silage

Pairs of lucerne silage stacks were made on six occasions starting spring 1970. One of each pair received formic acid at about 4 1/t. The other was untreated. The effects of formic acid on the resultant silage were assessed in terms of chemical analysis, digestibility, voluntary intake by sheep, and live‐weight gain by sheep and cattle fed the silages as sole diets. Formic acid silages contained more organic matter (85.7 v . 82.6%) and digestible organic matter (56.4 v . 48.7%) and less fibre (35.9 v . 40.4%) than untreated silages, but had lower levels of ammonia (9.4 v . 24.2%), pH (4.36 v . 5.22), and total volatile fatty acids (3.1 v . 7.6%). Daily dry matter intake was: formic acid silage 62.6 and untreated silage 45.6 g/LW 0.75 . Daily live‐weight gains on formic and untreated silages respectively were: sheep 18.8 and — 32.4 g; cattle 442 and 60 g.