Rumination in sheep. I. The influence of rumination and grinding upon the passage and digestion of food

Abstract

The nutritional significance of rumination was investigated in relation to certain aspects of rumen function, by using:(a) a chaffed roughage ration on which rumination was either allowed to occur normally or was restricted by means of a muzzle, and (b) a finely ground ration with either the normal rumination or with the addition of polyethylene flakes to stimulate rumination. An apparatus for recording jaw movements was used to measure the extent of rumination. Compared with the chaffed ration, grinding resulted in a shorter retention time of stained particles in the digestive tract, and lower apparent dry matter, organic matter, and crude fibre digestibilities. The addition of polyethylene flakes to the ground ration tended to further decrease retention time and caused a lowering of apparent dry matter, organic matter, and crude fibre digestibilities. The effect of muzzling, to restrict rumination, was to markedly increase the retention time, and this was accompanied by higher apparent dry matter, organic matter, and crude fibre digestibilities than when rumination was not restricted. Supplementary rumen metabolic data are presented. The importance of the mechanical activity in the digestive process is stressed.