The Ethanol Boom

All that corn-derived ethanol coming on stream means a more plentiful supply of distillers grains. Let's look at what it could mean to your feeding program.

Look no further than North America's ethanol industry boom to see what's been driving up your feed costs for grains like corn, barley and wheat. However, a by-product of this boom is potentially cheaper protein and energy sources.

Fuelling the boom are government policies in Canada and the U.S. promoting ethanol as a partial replacement for or additive to gasoline. New ethanol plants are on the drawing board or under construction on both sides of the border.

One U.S. industry estimate projects that by 2010 corn demand from U.S. ethanol plants will reach 140 million tons per year, or almost half the 300 tons harvested each fall. That amount would produce 50 million tons of dried distillers grain a year.

Expect to see more of this feed in Canada, too. For example, a new production facility in Hensall, Ont. expects to need at least 20 million bushels of corn a year when fully operational in 2008.

A U.S. Department of Agriculture report issued last summer notes that every bushel of corn used for ethanol produces about 17 pounds of dried distillers grains at 13 per cent moisture. One pound of this byproduct nutritionally equals about half a pound of corn and half a pound of soybean meal.

As well as dried distillers grains, ethanol by-products include wet corn distillers grains, corn gluten meal and corn gluten feed. Corn distillers grains [CDG] coming from the ethanol industry contain 30 to 36 per cent or more crude protein on a dry matter basis. The 2001 National Research Council [NRC] report lists CDG as 29.7 per cent crude protein.

Most of the readily degradable starches and sugars in corn going through the ethanol production process have probably been degraded during the fermentation process. So, the percentage of protein remaining in CDG is proportionally higher than in the original corn and higher in bypass protein.

How much CDG can be put into your dairy herd's diet? A South Dakota State University study looked at feeding dried and wet CDG as 10 and 20 per cent of the diet.

Cows fed this amount of distillers grains had greater feed efficiencies and milk quality profiles than cows fed control diets with no distillers grains. The cows fed wet CDG actually had higher butterfat and protein concentrations in their milk.

Another South Dakota trial looked at replacing corn and soybean meal with wet corn distillers grains and the effect on milk production. Diets for two groups of Holsteins consisted of a corn silage and alfalfa base, and either had corn and soybeans or corn and wet distillers grains as shown in Table 1.

The results showed that while feed intake decreased 10 per cent, milk production was not affected. However, the cows did retain less body energy when fed wet corn distillers grains.

When the feedstuffs were analysed, the CDG was found to have energy estimates 10 to 15 per cent greater than reported by NRC in 2001. This may be one reason production stayed the same in diets formulated to book values.

Since some studies have shown that feeding more than 20 per cent wet CDG could result in lowered feed intake, you would have to use caution when the diet is less than 50 per cent dry matter. You could also run into ration formulation issues as you increase the CDG percentage. Protein content would be beyond acceptable limits. Also, the CDG is still low in lysine, the first limiting amino acid in high-percentage corn diets for dairy cows.

Your farm's management and distance from a CDG source would become factors in determining whether to feed wet or dry distillers grains. The wet product won't remain fresh and palatable past five to seven days during warm weather, although it might stay acceptable for up to three weeks in cool conditions.

Wet CDG is typically about 70 per cent moisture. In really cold weather it will freeze, making handling and blending with other ingredients difficult. It may make total mixed rations too wet, especially if other feedstuffs include corn silage, haylage or both.

The South Dakota studies and others found in literature searches would indicate that corn distillers grains can replace traditional corn and soybeans as energy and protein sources by up to 20 of the ration. Past 25 per cent, total feed intake by your milking herd will drop.

Dry corn distillers grains and products are easier to manage. They come at a higher cost, however, because they have to be dried.

Other ethanol industry by-products include corn gluten meal and corn gluten feed. Corn gluten meal is a high-protein supplement at 60 per cent crude protein. It can be fed in combination with other protein sources. Corn gluten feed, at 25 per cent crude protein, has reasonable energy that has to be compared to prices of other feed sources.

Check out the factsheet, Comparative feed values for ruminants, on the Ontario Ministry of Agriculture, Food and Rural Affairs Web site for information on the nutritional values of by-products. It also shows how to cost out using these products.

Table 1. Diets comparing corn and soybeans with corn and wet CDG
  Corn and soybean diet by percentage Wet corn distillers diet by percentage
Corn Silage 31.4 31.4
Alfalfa Hay 18.4 18.4
Rolled Corn 30.7 17.0
Soybean Meal 16.7  
Wet Corn Distillers - 31.2

This article first appeared in the Ruminations column of The Milk Producer Magazine, February, 2007.

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