Dietary starch can increase milk protein and reduce milk fat content, but when fed in single meals may cause problems with rumen stability. To overcome the risk of acidosis, complete diet feeding or reducing the rate of starch degradation (by feeding sodium hydoxide treated whole wheat rather than ground wheat) may provide solutions. In addition, there is evidence to suggest that feeding high levels of cereals alters fatty acid composition of body fat (Garton et al 1972), and similar changes may occur in milk fat.

Ninety six multiparous Holstein cows were fed grass silage to appetite and supplements designed to provide increasing amounts of wheat starch either as wheat ground to pass through a 3 mm screen (GW) or as sodium hydroxide treated whole wheat (STW), prepared by adding 30 kg sodium hydroxide per tonne of wheat plus water to bring the total dry matter to 700 g/kg, and stored for 5 days before feeding.