Studies on the diet of the grazing animal. I. Seasonal changes in the diet of sheep grazing on pastures of different availability and composition

The diet of grazing sheep was studied by using animals with oesophageal fistulas. Seasonal changes in the botanical and chemical composition of the diet when grazing Phalaris–annual grasses–subterranean clover pasture are described. The effect of grazing intensity on diet is considered. A comparison was made of diets on seven pasture species. None of the species examined had a useful qualitative superiority over Phalaris either in winter or in summer, when the digestibility of this species declines considerably. Relations between botanical and chemical composition of the diet and the pasture are discussed. Significant relations were established between the nitrogen and soluble carbohydrate contents of diets and their digestibility.