Rates of loss from the reticulo-rumen of cattle of carbohydrate fractions (soluble sugars, water-soluble polysaccharides, pectin, hemicellulose, cellulose, and lignin) in single feeds of red clover (fresh or hay) have been followed by analysing representative samples of total rumen contents taken immediately before and after feeding and three, six, 12, and 22 hours after feeding. Rumen microbial polysaccharides were shown not to interfere to a serious extent in the measurement of all fractions except possibly the water-soluble polysaccharides. About 80 of the soluble sugars had disappeared by the end of feeding. Pectin was lost somewhat more slowly from the rumen but at a more rapid rate than the insoluble cell wall polysaocharides. Of these latter fractions hemicellulose was lost at a steady rate from the end of feeding, with arabinose being lost faster than xylose. Deteotable cellulose loss did not normally occur untn three hours from the end of feeding, after which it was lost at a steady rate. Lignin loss was slowest, being scarcely detectable until at least six hours from the end of feeding. Rates of loss tended to be slower with feeds of hay as compared with fresh clover.
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