Effect of stage of maturity of perennial ryegrass on its content of some organic acids and phenolic compounds

S24 perennial ryegrass was harvested at six stages of growth ranging from young leafy grass with no stem tissue to mature herbage cut when the seed was ripe. The contents of crude protein, lignin, total o ‐dihydroxyphenolic compounds and of chlorogenic, shikimic, quinic, succinic, malic and citric acids were determined in the grass samples from each cut and their distribution between leaf, stem and seed head tissue was examined. The decreases observed in the contents of malic, quinic and chlorogenic acids and of total o ‐dihydroxyphenolic compounds with increasing maturity of the herbage were linearly related to both the decrease in the proportion of leaf tissue and the increase in the lignin content of the herbage. The significance of the alicyclic acids, shikimic and quinic acids, and of the phenolic acids as dietary precursors of urinary aromatic acids in ruminants is discussed.