Rumen capacity together with speed of rumen emptying limit voluntary intake of low quality well balanced forages (Ellis et al., 1983). Chemical composition and physical processing have important effect on both digestion plus absorption and passage through the reticulo-omasal orifice. Feeding chopped forage generate a large rumen pool of coarse particles which must be broken down by chewing and ruminating before to have a chance to escape from the compartment (Grovum, 1983). Grinding, by contrast, greatly reduce this rumen pool increasing likelihood of particles to leave the foregut (Rodrigue and Allen, 1960). This paper aims to study the effect of physical processing of roughage on feeding behaviour and digestive kinetics together with voluntary intake and digestibility.