Progress in defining the differences in nutritive value to sheep of Perennial Ryegrass, Short-Rotation Ryegrass and White Clover

M.J. Ulyatt

Plant Chemistry Division, DSIR, Palmerston North

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Proceedings of the New Zealand Society of Animal Production. 1969, 29: 114-123

Measurements of intake and subsequent digestion of perennial ryegrass (P), short-rotation ryegrass (S) and white clover (C) were made on free-grazing sheep under conditions where there were significant differences in liveweight gain between the treatments.

The difference in animal response between P and S was attributed to differences in physical breakdown of the feed in the rumen. S which is physically weaker, and has less cellulose was digested less in the rumen and more in the lower digestive tract than P. It is thought that the S-animals might benefit from this post-ruminal digestion. There was no difference in the intakes of P and S.

Clover contained less structural carbohydrate and had a higher ratio of readily fermentable to structural carbohydrate than the ryegrasses. This led to a more intense rumen digestion, a higher concentration of end-products of rumen digestion, and a higher intake of C than S or P.

Differences in rumen volatile fatty acid proportions between the treatments were not thought to contribute significantly to differences in animal performance.

Keywords: NZSAPAB;

Last Updated 24-08-2000