Published online by Cambridge University Press: 27 March 2009
1. Data from eleven forages fed in digestibility trials were used to obtain statistical relations between organic matter intake (I), faecal dry matter output (F) and the concentration of nitrogen (N), copper (Cu), magnesium (Mg) and silicon (Si) in faecal dry matter.
2. Exploration of multiple regressions using all variables, and their products, gave a prediction relationship with four variables that was slightly better than that for nitrogen alone, as obtained by Arnold & Dudzinski (1963). FN and the products of(FN × FCu) and (FN × FSi) were the contributing variables. The eleven forages could not be brought into a single expression.