As cattle feeders use more ethanol co-products such as distillers’ grains in rations, questions arise regarding potential impact on beef quality. At the 2007 ProBeef Conference held in Ames, Iowa, in early September, Fred Owens, a nutritionist with Pioneer Hi-Bred, presented a review of research on the topic. He noted the following conclusions.

At dietary levels up to 40 percent of diet dry matter, distillers’ grains appear to have little impact on carcass grade and beef quality. However, at levels above 40 percent marbling scores are reduced, probably due to the high fat content of the ration.

Fresh beef color was brighter for cattle fed moderate levels of distillers’ products, possibly due to greater vitamin E intake.

Feeding ethanol byproducts at any level speeded beef rancidity, perhaps due to higher concentrations of polyunsaturated fatty acids in beef.

In addition to affecting carcass quality, distillers’ grains fed at levels higher than 40 percent of dry matter provide levels of protein and phosphorus well above requirements for feedlot cattle, resulting in excess nitrogen and phosphorus excretion. Excess unsaturated fat may depress intake and energy value, and high sulfur intake could depress intake and cause polioencephalomalacia, especially where water is rich in sulfur.

IowaStateUniversity has posted the complete proceedings of the ProBeef Conference on the Iowa Beef Center Web site. The proceedings included 15 presentations on topics related to ethanol and beef production. You can find the presentations by following this link.