Published online by Cambridge University Press: 27 March 2009
It is generally recognized that there is a close relationship between the utilization of roughage feed and rumination behaviour in ruminant animals (Gordon, 1955, 1968; Pearce & Moir, 1964; Campling, 1966; Welch & Smith,1969; Sudweeka et al. 1975; Thomas, Kelly & Wait, 1976; Fujihara, 1981). Likewise, it is also well known that rumination behaviour is clearly affected by differences in the physical and/or chemical properties of the diet (Gordon, 1958; Campling, Freer & Balch, 1962; Balch, 1971; Ørskov, Fraser& Gordon, 1974; Osuji, Gordon & Webster, 1975; Morgan & Campling,1978; Harumoto & Kato, 1978a, b; Fujihara, 1980b). Recently, Fujihara (1980a, b) observed more efficient rumination in sheep offered fresh grass than hay, and suggested that the efficient rumination might induce an efficient utilization of dietary nitrogen when feeding fresh grass.