Most of the distillers grains currently being produced are consumed by the domestic livestock and poultry industries, especially the beef industry.

A recent study by the Center for Agricultural and Rural Development projects that the U.S. ethanol industry could produce between 40 million and 88 million metric tons of distillers grains (dry matter basis) per year by 2011. The proportion of these distillers grains that would need to be consumed by the beef industry to prevent surpluses poses questions about how much distillers grains can be included in beef rations, the effects of feeding distillers grains on beef quality, and how current consumption patterns are likely to change as production of distillers grains increases.

As more data from feeding trials have become available, a better understanding of the benefits and effects of feeding distillers grains is emerging. In this paper, we use results from a recent USDA producer survey about co-product use in beef production to project how current patterns of use are likely to change as the volume and availability of distillers dried grains increases. We then review recent results from feeding trials using distillers grains in beef rations, including nutritional value and effects on live animal performance and beef quality. Finally, we discuss some of the new technologies being used to improve distillers grains as a ration ingredient and present some general conclusions.

Introduction

The ongoing expansion in U.S. corn-based ethanol production has generated concern that the ethanol industry will create large surpluses of co-products. Expected production levels are, indeed, high. Using a relatively conservative set of assumptions, a recent study by the Center for Agricultural and Rural Development (CARD) projects that the U.S. ethanol industry will produce nearly 15 billion gallons of ethanol and 40 million metric tons of distillers grains (dry matter basis) per year by 2011.1 Under a much more aggressive set of assumptions, the CARD study projects that ethanol production could reach nearly 30 billion gallons annually by 2016, generating more than 88 million metric tons of distillers grains per year (Tokgoz et al. 2007).

Some U.S. distillers grains are exported, but the primary users are the domestic livestock and poultry industries, especially beef and dairy cattle because ruminants are best suited to the low starch and high fiber levels in conventional distillers grains. As will be discussed in this paper, estimates vary on how much distillers grains can and should be used in rations. A recent USDA report states that optimal inclusion levels are 30 per cent to 40 per cent in beef rations, although higher rates can be used (Westcott 2007).2 Beef feeding trials have shown that excellent performance has been achieved at inclusion levels of 40 per cent to 50 per cent (Loy 2007). By comparison, “recommended maximum inclusion levels are 20 to 25 percent for dairy, 20 percent for growing and finishing hogs, and 15 percent for the grower and finisher stages of poultry feeding” (Westcott 2007, p. 12). USDA (2007a) estimates that beef cattle consume about 80 per cent of the distillers grains being fed to domestic livestock and poultry.

The projected volume of distillers grains that will need to be consumed to prevent surpluses as production increases has raised questions about the amount of distillers grains that can reasonably be included in beef rations and whether high inclusion levels affect beef quality. As more data from feedings trials have become available, a better understanding of the benefits and effects of feeding distillers grains is emerging to help answer these questions. In this paper, we review several of the studies from the growing body of research examining the use of distillers grains in beef production.

Following a brief overview of distillers grains for beef rations, we use data from a recent USDA producer survey to evaluate the potential for increased co-product use and how patterns of use in beef production may change as the volume and availability of distillers grains increase. Then, we summarize recent research regarding nutritional and environmental factors that affect optimal, practical, and maximum inclusion levels of distillers grains in beef rations and the effects of inclusion on animal performance and beef quality. Finally, we discuss new technologies the ethanol industry is already using or may adopt to improve distillers grains as an ingredient for livestock and poultry rations and present some general conclusions.

Distillers Grains for Beef Rations

The two basic systems for corn-based ethanol production are the wet milling process and the dry grind process. The main co-products of the wet milling process used in livestock feeds are corn gluten feed, corn gluten meal, and condensed steep water solubles. The main co-products from the dry grind process used in livestock feeds are distillers grains and condensed distillers solubles.

In 2006, more than 70 per cent of corn-based ethanol was produced at dry grind plants. This percentage is expected to increase because “all newly constructed ethanol plants employ some variation on the basic dry grind process because such plants can be built at a smaller scale for a smaller investment” (Mosier and Ileleji 2006). Given the increasing dominance of the dry grind process, this paper focuses on distillers grains as the primary co-product that will be available for use in beef cattle rations as ethanol production increases.

Further Reading

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