Effect of red clover/timothy ratio on the protein feeding value and the quality of silage

Abstract

Five silages having different proportions of red clover and timothy (100/0, 75/25, 50/50, 25/75 and 0/100) were preserved in five glass-fibre silos of 0.4 m 3. Chopped red clover and timothy were mixed during ensiling and preserved with AIV II solution (80 % formic acid and 2 % orthophosphoric acid), applied at the rate of 6 l/1000kg fresh material. The timothy sward was fertilized with 100kg N/ha and the red clover with 15kg N/ha. The dry matter content in red clover was 14.5 % and in timothy 18.6%, and the crude protein content of DM 22.9 % and 11.5 %, respectively. True protein formed 75—76 % of crude protein in both herbages and the proportion of watersoluble N in total N was 32 % in red clover and 36 % in timothy. The rumen degradability of protein during the first two hours was under 10 % in both herbages; after 18 and 24h ours it was 76 % and 87 % in red clover, and 65 % and 70 % in timothy. In red clover the contents of lysine, methionine and cysteine were 5.7 g, 0.4 g and 0.9 g/16 g N, respectively, the corresponding values for timothy being 4.8 g, 0.7 g and 1.4g/16 g N. In red clover the content of water-soluble carbohydrates was 10.6 % of DM and in timothy 16.5 %; the contents of plant acids were 6.7 % and 3.5 % of DM, respectively. Red clover contained 10.9g Ca/kg DM and timothy 3.1 g Ca. The total amount of inorganic constituents was also higher in red clover than in timothy. Although the chemical composition of red clover was less suitable for ensiling than the composition of timothy, the quality of all the silages was good. During ensiling the decrease in the proportion of true protein in crude protein and the increase in the proportion of watersoluble N in total N were smaller in red clover than in timothy silage. These changes were reflected in the ruminal protein degradation, which seemed to be slower when they were small. The amino acid profile of the protein did not alter during ensiling. The ensiling losses were higher in the silages containing red clover than in the timothy silage. This conserned especially the effluent losses and surface spoilage of the feed.