Forage Composition and the Conduct of Digestion Trials for the Comparative Evaluation of Laboratory Procedures

Fifty‐four grass, legume and whole‐crop maize forages were frozen and fed to sheep in amounts calculated to meet their daily DOM requirements for maintenance. The mean level of feeding achieved was 1·01±0·014 ± maintenance, and the mean and median values of the standard error of means of the coefficients of apparent DM digestibility determined were 0·66 and 0·50 percentage units. The range in composition of the forages was: cell walls 25·0– 64·2, digested cell walls 15·1–50·0, and apparently digested organic matter 56·4 to 76·1 g/100 g DM. The proportion of the DOM arising from cell walls had an even greater range (22–72%) and differed markedly between the forage species in mean value and in respect of the trend with advancing maturity. It was concluded that the conduct of the digestion trials and the range in composition of the forage samples examined were adequate to provide samples of herhage suitable for the comparison of laboratory procedures of forage evaluation.