The effect of trichloroacetamide, chloroform and linseed oil given into the rumen of sheep on some of the end-products of rumen digestion.

I. Twelve sheep were offered a diet of hay and molassed sugar-beet pulp for 18 weeks, and from the 3rd to the 16th week the sheep were divided into four groups of three; one of each of the groups received daily 170 mg trichloroacetamide, 140 mg chloroform, 30 g linseed oil or no additive. 2. The additives had no significant effect on the apparent digestibility of the dry matter, organic matter, nitrogen or energy of the diet. 3. When either trichloroacetamide or chloroform was added to the diet, methane production was almost totally suppressed and some hydrogen w a s produced but, although these changes persisted with chloroform, they were much reduced after 28 d of trichloroacetamide administration. When linseed oil was added to the diet the methane production was reduced by almost