The estimation of digestible energy intake from forages by ruminants

Abstract

Twenty air-dried or fresh-frozen herbages were fed to sheep in digestibility trials. Chemical fractions of the herbage and faeces, as well as in vitro estimates of herbage digestibility, were related to the digestible energy (DE) and digestible organic matter (DOM) ratios. The lignin ratio between faeces and herbage was more closely related to the DE and DOM ratios than other indices examined. Lignin recovery was 98.3 ± 1.2 per cent. Residual standard deviation in relating actual to estimated DE intake was 9.6 per cent, when the DOM ratio was estimated from the lignin ratio and DE intake, calculated by using the observed mean energy value of 4.59 kcal/gm for DOM. The results indicate the lignin ratio technique, as applied, will give a considerably more accurate estimate of herbage digestibility than the alternative techniques examined