Effects of pasture maturity on the diet of sheep

Abstract

This paper compares the changes from early spring to summer in the digestibility of the diet of sheep grazing on phalaris -subterranean clover pasture, with changes over the same period of a similar pasture cut. and fed to sheep in pens. Data from a continuous digestibility trial in pens between September and December 1958 showed that the voluntary dry matter intake of sheep was restricted when the dry matter content of the pasture was below about 25%. From an early vegetative stage of growth through to early flowering of the phalaris, the organic matter digestibility of the whole pasture declined only from 79 to 76%. The diet selected by grazing sheep did not decline in digestibility, as measured by a faecal nitrogen index method, until 2 or 3 weeks after the decline in the whole pasture. With flowering and senescence of the pasture, the organic matter digestibility declined rapidly to 53%. Factors influencing this marked decline are discussed.