Publication Date:
1983-08-01
Description:
SUMMARYA total of 21 rumen-cannulated wether sheep and six rumen-cannulated Ayrshire cows were used in a series of experiments to investigate fermentation in the rumen in animals given silage diets and the nominal metabolism of silage lactic acid. Dietary experiments with sheep (three experiments) and cows (two experiments) given diets consisting of formic acid–preserved perennial ryegrass (Lolium perenne) silages, in some cases with supplements of rolled barley, were conducted to investigate the ruminal concentrations of lactic acid and of volatile fatty acids (VFA) after feeding. Ingestion of silage was followed by a short-lived peak in lactic acid concentration in the rumen and by a subsequent increase in the concentration of propionate or propionate and butyrate. Butyrate production was more evident in cattle than in sheep. Taken as an average over a 6 h period of sampling the proportions (m-mol/mol total VFA) of acetate, propionate and butyrate in the rumen in animals given silage alone were typically 590–600, 210–250 and 70–150 respectively. When silage was supplemented with barley, in both sheep and cattle, the proportion of propionate was reduced and the proportion of butyrate was increased. In one experiment with sheep these changes in fermentation pattern were shown to be accompanied by an increase in the number of rumen protozoa from 2·78×105/ml to 18·66·105/ml (P
Print ISSN:
0021-8596
Electronic ISSN:
1469-5146
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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