Pastures and grazing animals

The moisture content of grass is of particular importance when a crop is being harvested for conservation it is high in very yoimg material, usually 750-850 g/kg, and falls to about 650 g/kg as the plants mature. Weather conditions, however, greatly influence the moisture content. 

Proximate composition Carbohydrates Nitrogenous components Other constituents 

The composition of the dry matter is dependent on the relative proportions of cell walls and cell contents. The cell walls consist of cellulose and hemicelluloses, reinforced with lignin. The cellulose content is generally within the range of 200 300 g/kg DM and that of hemicelluloses may vary from 100 g/kg to 300 g/kg DM. The concentrations of both these polysaccharide components increase with maturity so also does that of lignin, which reduces the digestibility of the polysaccharides. 

The amino acid composition of forages is clearly important when the feeds are used as protein sources for non-ruminants. For ruminants, however, the most important characteristics of forage proteins are their rumen degradability and their overall digestibility. In immature forages, both measures are commonly very high (0.7-0.8), 

The mineral content of pasture is very variable, depending upon the species, stage of growth, soil type, cultivation conditions and fertiliser application an indication of the normal range in content of some essential elements is given in Table 18.2. 

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