The nutrient composition of grains

The hpid content of cereal grains varies with spedes. Wheat, barley, rye and rice contain 10 30 g/kg DM, sorghum 30-40 g/kg DM and maize and oats 40-60 g/kg DM.The embryo, or germ, contains more oil than the endosperm in wheat, for example, the embryo has 100-170 g/kg DM of oil, while the endosperm contains only 10-20 g/kg DM.The embryo of rice is exceptionally rich in oil, containing as much as 350 g/kg DM. Cereal oils are imsaturated, the main adds being linoleic and oleic because of this they tend to become rancid quickly and also produce a soft body fat in pigs and poultry. 

Starch occurs in the endosperm of the grain in the form of granules, whose size and shape vary with different species. Cereal starches consist of about 25 per cent amylose and 75 per cent amylopectin, although waxy starches contain greater proportions of amylopectin. 

Calves, pigs and poultry depend upon cereal grains for their main source of energy, and at certain stages of growth as much as 90 per cent of their diet may consist of cereals and cereal by-products. Cereals generally form a lower proportion of the total diet of ruminants, although they are the major component of the concentrate ration. 

Barley Hordeum sativum) has always been a popular grain in the feeding of farm animals, especially pigs. In most varieties of barley the kernel is surrounded by a huU, which forms about 10-14 per cent of the weight of the grain. 

The hpid content of barley grain is low, usually less than 25 g/kg DM.The range in dry matter composition of 179 samples of barley grain harvested in Wales is given in Table 22.2. 

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