Corn co-products as replacements for high-priced corn and soybean meal

By Dr. Hans H. Stein

February, 2011

Distillers dried grains with solubles (DDGS) is the most common co-product generated from the ethanol industry and the production in the US of DDGS is now greater than the production of soybean meal. While DDGS is an excellent feed ingredient that in most cases can be included in diets fed to all groups of pigs at levels of at least 20 to 30%, there are also other corn co-products that may be used in diets fed to pigs.

From the ethanol industry, there is production of high protein distillers dried grains (HP DDG) and corn germ if the ethanol plant is using front-end fractionation. Both of these products are excellent feed ingredients and HP DDG may replace all the soybean meal in diets fed to pigs from they are approximately 40 kg and for younger pigs, HP DDG may be used in concentrations of 20 to 30%. At these inclusion levels, pig performance will usually be maintained provided that diets are formulated in such a way that they are balanced for indispensable amino acids. This often means that diets need to be supplemented with synthetic sources of lysine and tryptophan.

Corn germ contains approximately 18% crude fat and may be included in diets fed to growing-finishing pigs by up to 30%. At this inclusion rate, pigs usually have great performance and feed intake is often improved when corn germ is included in the diet.

Corn gluten meal and corn gluten feed are co-products of the wet milling industry. Corn gluten meal contains approximately 60% crude protein and may be included in diets fed to growing-finishing pigs by 20 to 25%. As is the case when other corn proteins are used, diets containing corn gluten meal need to be fortified with synthetic sources of lysine and tryptophan to balance all the indispensable amino acids.

Corn gluten feed is a high fiber ingredient that usually contains around 22% crude protein. There are no good data investigating consequences of including corn gluten feed in diets fed to pigs, but the high fiber concentration limits the inclusion levels. At this point it is, therefore, recommended that corn gluten feed is included by less than 20% in diets fed to growing-finishing pigs and by less than 10% in diets fed to weanling pigs.

Corn germ meal is a co-product from both the dry-milling industry and the wet milling industry and consists of the defatted corn germ that is produced after the corn oil has been removed from corn germ. Corn germ meal, therefore, contains only around 2% crude fat and is very high in fiber and it is recommended that no more than 20% is included in diets fed to growing-finishing pigs and no more than 10% in diets fed to weanling pigs. It is important to note the difference between corn germ and corn germ meal – corn germ is the high-fat co-product that has an energy content that is close to that of corn. Corn germ meal, in contrast, is a low fat product that contains much less energy than corn.

Hominy feed is a co-product of the corn-grits industry. The concentration of crude protein in hominy feed is low (less than 10%), but there is usually between 40 and 50% starch left in hominy feed. It is, therefore, possible to replace a large portion of the corn in diets fed to swine if hominy feed is used, and inclusion levels of up to 50% may be used in diets fed to all categories of pigs.

Thus, as the costs of traditional feed ingredients are increasing, there are a number of alternatives that may be used to help reduce diet costs. A summary of recommended inclusion levels for these co-products is available in Table 1.

Table 1. Recommended inclusion of corn co-products in diets fed to weanling and growing-finishing pigs

 

Maximum dietary inclusion, %

Ingredient

Weanling pigs

Growing-finishing pigs

  DDGS

30

30

  HP DDG

30

40

  Corn germ

15

30

  Corn gluten meal

15

25

  Corn gluten feed

10

20

  Corn germ meal

10

20

  Hominy feed

40

50

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