THE DIGESTIBILITY OF THE LEAVES AND STEMS OF PERENNIAL RYEGRASS, COCKSFOOT, TIMOTHY, TALL FESCUE, LUCERNE AND SAINFOIN, AS MEASURED BY AN <i>IN VITRO</i> PROCEDURE

Determinations of the in vitro digestibilities of leaf‐blade, leaf‐sheath and stem fractions of the grasses cocksfoot, perennial ryegrass, timothy and tall fescue and of the leaves and stems of lucerne and sainfoin have shown that all parts of the plant have a high digestibility at early stages of growth. With increasing maturity, however, the digestibility of the stem falls off at a much faster rate than that of the leaf; in grasses, leaf‐sheath digestibility declines at an intermediate rate. The decline of digestibility is associated with a reduction in the content of water‐soluble and protein constituents in the plant, and with a reduction in the digestibility of fibre. This may provide a biochemical basis for the selection of forage plants of high digestibility in plant‐breeding studies.