Comparison of methods of preparing grass and silage samples for laboratory analysis

Abstract

The effects on the estimated chemical composition of grass and silage of various methods of preparing samples for analysis were studied. The methods used for grass were: (1) oven drying and grinding, (2) freeze drying and grinding, (3) coring, (4) mincing, and (5) freezing and sawing; and for silages: (1) freezing and sawing, (2) mincing, (3) slicing with a bacon ,,~icer once or twice, and (4) chopping with a hand guillotine. Oven drying of grasses gave lowest values for dry matter (DM), soluble carbohydrate, and total N, but method of preparation had no effect on ash % or fibre %. DM and fibre contents of silages were highest in minced and frozen-sawn samples, but method of preparation had no significant effect on values for VFA, lactic acid, and ammonia.