Bloat in cattle

Abstract

Summary Crude rumen liquor from cows fed on red clover was fractionated in order to separate and estimate soluble polysaccharides, plant and protozoan starch, and bacterial capsular polysaccharides. The animals used included a pair of identical twins under both bloating and nonbloating conditions. The concentration of polysaccharide in cell-free rumen liquor was low and no greater in bloating than non-bloating animals. The hot-water extract of the solids centrifuged out of the crude rumen liquor yielded a fraction which, in non-bloating animals, showed a considerable increase on feeding. In animals which bloated, the initial level was higher than in non-bloating animals but showed no marked increase after feeding. Control of bloat by penicillin administration also prevented an increase in this fraction. The concentration of capsular polysaccharide in the fraction obtained by an acetic acid decapsulation technique applied to the centrifuged solids from rumen liquor, showed no correlation with bloat incidence. Much of the polysaccharide present in the isolated fractions was starch, probably of the amylopectin type. Positive tests for dextran were not obtained in any of the fractions.