Some effects of shading and of nitrogen fertiliser on the chemical composition of freeze‐dried and oven‐dried herbage, and on the nutritive value of oven‐dried herbage fed to sheep

An experiment is described in which the nutritive value and chemical composition of oven‐dried herbage from shaded perennial ryegrass pasture (SR) were compared with those of unshaded ryegrass (R), shaded + nitrogen‐fertilised (SR + N), and unshaded + nitrogen‐fertilised (R+N) ryegrass herbage, and with those of white clover (C). Higher food intakes and live weight gains were found with C herbage than with the ryegrass herbage (SR, R, SR + N, R + N = P), and with unshaded than with shaded herbage. Application of nitrogen fertiliser prior to harvesting did not affect live weight or food intake. A higher D.M. digestibility was found for C than for P herbage, and in the second trial only, a higher digestibility was evident for unshaded than for shaded, and for nitrogen than for no nitrogen treatments. A higher proportion of soluble carbohydrate and lignin, but lower hemiccllulose and cellulose content, were found in dried C than in P herbage. Shading perennial ryegrass pastures reduced the proportion of soluble carbohydrate and increased the proportion of cellulose and lignin. Nitrogen fertiliser reduced the proportion of cellulose and lignin in dried herbage. Freeze‐dried herbage had a higher soluble carbohydrate, but lower insoluble carbohydrate, content than oven‐dried herbage.