Value and use of by-products in the cow herd
Rick Rasby, Beef Specialist, UNL
Corn byproducts, particularly those obtained from ethanol production processes, can be effectively used to supplement protein or energy for backgrounding cattle or in heifer and cow diets, according to Rick Rasby, University of Nebraska-Lincoln (UNL) beef specialist. But, considerable difference exists between corn gluten feed byproducts obtained from wet milling and distillers grains obtained from dry milling in terms of nutritional value, he warned attendees of the 2003 Range Beef Cow Symposium.
Because corn-milling product supplies will increase with growth in the ethanol industry, beef specialist Rick Rasby encouraged producers to use more byproducts when priced competitively.
"A number of factors can impact the nutrient profile of distillers grains, such as moisture content, grain selection, ratio of grains and distillers solubles included in the product, continuous versus batch fermentation, as well as drying temperature and duration," he said. Moisture variation may pose the biggest challenge in managing wet byproducts. Producers should get a feed analysis that includes moisture content and other nutrients."
In general terms, Rasby said both corn gluten feed and distillers grains are good sources of protein. Distillers grains are high in UIP (undegraded intake protein) and make an excellent feed for young, growing cattle and lactating cows. Corn gluten, as a protein source, is high in DIP (degradable intake protein) and nitrogen for rumen microbes.
Both products also can supply energy. Cows may require energy through the winter, during early spring following calving, or for replacement heifers. When forage quality is poor or quantity is limited by drought, byproducts may have an ideal fit. Both byproducts work well in cornstalk grazing situations, while dry distillers grains may be an attractive grazing supplement when forage prices are high or forage is limited.
"The energy value of wet distillers grains is 125% or more the energy value of (commodity) corn," Rasby told producers. "Wet corn gluten feed varies from equal to or slightly higher energy than corn, depending on the amount of steep liquor. When corn gluten feed is dried, the energy value of the feed is reduced."
When direct comparisons are made, the energy value of wet products is superior, with little difference in protein quality, he added. Both byproducts may supply DIP and UIP; reduce or eliminate negative associative effects; alleviate acidosis; or have positive, related effects that complicate comparisons to traditional energy and protein sources.
Because corn-milling product supplies will increase with growth in the ethanol industry, Rasby encouraged producers to use more byproducts when priced competitively.
by Barb Baylor Anderson
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