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Livestock in bioenergy production

Jim Linn and Mary Raeth-Knight

Published in Dairy Star March 2007

This month we are going to deviate a little from dairy nutrition and highlight how animal agriculture fits into bio or renewable energy production. As our state and federal governments discuss and pass legislation on renewable energy, we need to tell people about the important role animal agriculture will play in the success of any current renewable fuel production plan.

All livestock producers have been faced with higher feed costs as the price of corn has increased to over $4.00 per bushel. Poultry feeding costs have increased over 18% and it is estimated that dairy feeding costs have increased nearly $1.00 per cow per day as corn and other feed prices have increased. As feed costs increased, livestock nutrition programs have been forced to reevaluate the feeding of corn and soybean meal, and even alfalfa and corn silage in ruminant programs. While trying to cope with higher feed costs, let us not lose perspective on how animals are essential to the success of bio or renewable fuel production.

Animals are the world's best recyclers. In the case of ruminants, they convert plant fibers and other byproducts that are not suitable for human food into high quality, wholesome and nutritious food products. Corn is the staple in human and animal diets. But, as more corn goes into ethanol, how many of us are filling our plates with the ethanol byproduct distillers grains? Animals are "stepping up to the plate" and replacing corn in their diets with distillers grains. In 2006, the ethanol industry produced over 13 million tons of distillers grains. Dairy cattle consumed the largest portion at about 46% of the production followed by beef at 42%, swine at 9% and poultry at 3%. Some of the research now indicates we can feed more than 10 lb per day of dried distillers grains to dairy cows. Other livestock will eat less than 10 lb per day just because they eat less total feed per day than a dairy cow. For complete information on the nutrient content of distillers grains and feeding recommendations, visit the University of Minnesota DDGS website. Using other grains or starch sources for ethanol will not eliminate a distillers grain byproduct and animals will still be the best converters of this into high quality food products.

Switching from corn to cellulose material for ethanol production most likely will eliminate the use of byproducts in animal diets. The current process of acid and chemical treatments to breakdown the lignin in biomass material for conversion into ethanol will render any byproduct material unfit for feeding. Also, the cellulose and fiber material converted into ethanol is the same plant feed material that ruminant animals convert into animal products so any remaining byproduct from cellulosic ethanol production will have very little nutritional value remaining for animals. However, animals can contribute and are needed for cellulosic energy production other than through consumption of byproducts. The intensive harvesting of biomass (plant material) for ethanol production will remove nearly all the organic material and little to no crop residue will remain for maintaining soil fertility. Animal manure will benefit these soils as an excellent source of nutrients and organic matter to maintain soil fertility.

A future biomass cellulosic source may be alfalfa. The stems of the alfalfa plant will be separated from the leaves before being used to produce ethanol. Alfalfa leaf meal will be the byproduct, which is a high quality protein low fiber feed. Research we did several years ago on alfalfa leaf meal showed it was an excellent protein source for several animal species.

Soybeans are the major source of oil currently used in biodiesel. Removing the oil from soybeans leaves soybean meal, a feed the animal industry has been using for many years. Using other oilseeds, such as sunflowers, canola and flax, for biodiesel will result in an oilseed meal byproduct and these too are already being well utilized in animal diets. Animals can contribute directly to biofuels in that animal fats have the potential to replace soy oil or other oils as a biofuel.

Animal agriculture already has been and can make an even bigger contribution to renewable energy through bio-digesters. Farms like the Haubenschild's in central Minnesota have been converting dairy manure into methane and electrical energy for several years already. Digesting manure not only produces energy, but reduces manure odor and green house gas emissions, and the solids coming out of a digester make an excellent soil amendment or can be recycled as a bedding source for cows. In some areas with large poultry facilities, poultry manure is being burned as an efficient source of electricity and heat.

Animal agriculture is already significantly involved in all renewable, biofuel or biomass energy production. Animals, either through recycling byproducts or direct production of energy from manure, will be an essential component in our search for renewable energy and a substitution for fossil fuel. Let's continue telling our story about the importance of animal agriculture not only for food production, but now as an essential component in meeting renewable energy goals.

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