Learning to Live with Ethanol

Dried Distillers Grains with Solubles (DDGS) can be an attractive feedstuff for pork producers.
By Stewart Skinner

The ethanol industry has experienced rapid growth following the implementation of the Energy Policy Act of 2005. The act states that U.S. domestic production of renewable fuels should reach 7.5 billion gallons in annual production by 2012. In Canada, different provincial standards have been created to ensure that all gasoline contain at least 5 to10% ethanol. These two national policies have fostered a period of rapid and widespread expansion of ethanol distilleries that has caused an increase in demand for corn, as it is the primary feedstock in North American ethanol production. The increased demand for corn has caused prices to move higher and as such, prices for commodities that compete for acreage with corn has also increased. Hog producers are facing higher feeding costs because of higher prices for corn (an energy source) and soybean meal (a protein source) due to ethanol.

Dried Distillers Grains with Solubles (DDGS) are a by-product of ethanol and traditionally were not widely used by hog producers due to issues with product quality and nutritional variability. Improved manufacturing processes and technology have made DDGS a more attractive ingredient for swine producers and use of DDGS in hog feeds is becoming common across North America. Stewart Skinner, a M. Sc student at the University of Guelph has spent the last year researching how the adoption of DDGS can influence ration choice and the impacts that DDGS use may have on the excretions of nitrogen and phosphorus.

In a recent study, DDGS reduced the cost of feed by 12.8% when a three phase grow-finish diet was fed with a DDGS inclusion rate of 25%. DDGS acted as a substitute for multiple nutrients, most notably energy, crude protein (amino acids) and phosphorus. The majority of savings from DDGS were incurred through the partial replacement of corn, soybean meal, and di-calcium phosphate. The reduction in feed costs when DDGS is present is consistent with an Iowa State study conducted by Jacinto Fabiosa in 2008. It is consistent with recent trends noted by commercial feed sellers. Decreased feed costs leads to the conclusion that DDGS should be incorporated in swine feeds.

The rations including DDGS had higher levels of crude protein, total phosphorus and available phosphorus than the DDGS-free rations. The nutrient retention efficiency for nitrogen was reduced to 31.4% (from 36.3%) while phosphorus retention was reduced to 28.4% from 29.6%. Higher nutrient levels in the feed, together with lower nutrient retention ratios when DDGS are fed led to increased levels of nitrogen and phosphorus in the manure. When DDGS was included in the diets, excretion of nitrogen increased by 20.3% while phosphorus excretion increased by 6.5%.

While increased emissions of nitrogen and phosphorus from DDGS can be seen as negative, the overall impact of these increases depends on the nutrient management situation of the individual farm. Higher emissions of nitrogen and phosphorus may be overcome in certain environments; cropping strategies can be altered to increase the ability of crops to remove excess nutrients. The cost of these increased emissions is dependent on the regulatory situation of a given region. Hog farms in regions with strict environmental legislation will face higher costs due to increased emissions than farms in an area with little or no environmental regulation. Regardless of presiding regulations, fertilizer applications can also be adjusted to account for higher nutrient content in the manure. Increased nitrogen levels will allow for a decrease in purchased supplemental nitrogen, lowering costs for farmers who utilize swine manure as fertilizer.

The expansion of the ethanol industry has increased feed costs, however improved product quality has allowed greater use of DDGS in swine diets. This research supports previous findings that DDGS can lower feed costs, however the incorporation of DDGS changes the nutrient content of manure. Regional regulatory structure will determine the cost or benefit of increased emissions.

Editor’s Note:Stewart Skinner, a M. Sc student at the University of Guelph has spent the last year researching how the adoption of DDGS can influence ration choice and the impacts that DDGS use may have on the excretions of nitrogen and phosphorus under the supervision of Dr. Alfons Weersink and Dr. Kees DeLange. The information provided in this article is from his study.