Effects of nitrogenous fertiliser on the chemical composition of short-rotation ryegrass and its subsequent digestion by sheep

Abstract

“Nitrolime” was applied to a pure sward of short-rotation ryegrass (Lolium perenne × L. multiflorum) at high (HN) and low (LN) rates. The grass was fed to rumen-fistulated sheep housed indoors. Total, non-protein, protein, and nitrate nitrogen contents of the HN grass, were greater than in the LN grass on the first three of four sampling days. Total soluble sugar and water-soluble polysaccharide contents of the HN grass were lower than in the LN grass on the first two sampling days. Compared with the LN grass, the rumen liquor of the sheep on the HN grass contained higher concentrations of soluble nitrogen, soluble non-protein nitrogen, ammonia, and nitrate, lower total VFA concentration and proportions of butyric acid, and higher proportions of acetic acid. The difference in the proportion of propionic acid depended on the time of sampling. It was concluded that even though large treatment differences in grass composition were obtained, there were no marked deleterious effects en animal health or intake.