Corn grain has a high starch concentration and as such is used as energy source for cattle diets in many parts of the world. This starch is also used in the industry as a substrate to produce ethanol and sweeteners. Ethanol extraction from corn concentrates results in all other valuable nutrients being concentrated.
As a result, corn grain which has originally 7-9% crude protein concentration, once starch is extracted leaves a coproduct with much higher protein concentration (> 30%). The two most common corn starch processing methods in the industry today are dry milling (ethanol production) and wet milling (sweetener production), with both leaving high protein coproducts.
From ethanol production the coproduct obtained is distillers dried grains which has a crude protein (CP) concentration between 27-30%. The sweetener industry on the other hand, leaves corn gluten feed (25% CP) and corn gluten meal (60% CP).
More recently (1990’s), further fractionation has removed the fat, bran, and germ of the kernel further increasing the CP of the remaining coproduct to 40% CP or more. There is a novel proprietary high protein product with close to 56% CP that’s also available as a protein concentrate, particularly for dairy cattle.
There has not been a large body of research of these new fractionation coproducts, particularly compared to other, more traditional alternatives such as soybean meal and canola meal.