Recent developments in improving the prediction of digestibility of feed grains

Abstract

“Feed grain” has always been regarded as an inferior product in Australia because it is unsuitable for milling. However the recent sharp increase in the feeding of grains to livestock has resulted in a large collaborative research project being established to improve the quality and marketing opportunities for feed grain. This study addresses one of the project’s objectives which is to develop rapid tests for nutritional value, specifically dry matter digestibility (DMD) and hence metabolisable energy. In vivo DMD was measured on 40 grains in sheep using a standard protocol, with values ranging from 61.9 to 92.3% (standard deviation 6.64). NIR could predict in vivo DMD satisfactorily for whole grain (R2 0.92, SECV 1.94) and ground grain (R2 0.93, SECV 1.74). However a more even distribution of values is required for a robust relationship, with further samples having DMD values between 60 and 80%. Additional in vivo trials are in progress with 20 diverse grains using sheep, and 8 of these using cattle. These grain “standards” will form the basis of a uniform procedure for rapid prediction of DMD between Australian laboratories.