The development of the ethanol industry throughout Nebraska in the past 10 years has resulted in an abundant supply of distillers grains available for cattle feed. Additionally, a number of recent years have had high corn prices. This has made distillers grains a favorable supplement for pasture cattle.

However, there are regions where distillers grains are in limited supply, and transportation expenses make acquiring distillers grains less favorable. Today, corn prices are lower than they have been in a number of years, making corn — especially corn with lower transportation costs — very favorably priced for cattle producers.

DIFFERENCE IN STARCH: One of the big differences between corn and corn distillers grains is the starch content. (Photo credit: Troy Walz, UNL Extension educator)

Regardless of the commodities available, there are a couple of things producers should think about before purchasing supplement.

The first thing producers need to consider is the requirement of the cattle on the pasture. Mature, gestating, dry cows have a different requirement for protein and energy than lactating cows, and growing calves will have different needs from cows.

The second thing producers need to know is the quality of the pasture being grazed. Cattle prices are much lower this year than the last couple years, and producers are not going to want to spend money unnecessarily on supplement. University of Nebraska beef Extension personnel can help producers calculate balanced supplement needs.

While corn can be an acceptable supplement, there are several differences that must be considered when substituting corn for distillers grain as a pasture supplement for grazing cattle.

One of the big differences between corn and corn distillers grains is the starch content. Corn is about 73% starch, while corn distillers grains has only trace amounts of starch since it is used for ethanol production. This is important, because starch can have a negative impact on fiber digestion: it shifts the microbial population in the rumen away from fiber digesters. Obviously, if cattle are grazing grass they need to be able to effectively digest grass.

The total digestible nutrients (TDN), a measure of energy, are only 83% for corn when used in a roughage-based diet. Distillers grains, which are high in digestible fiber and contain some corn oil, have actually been determined to be 108% TDN in forage-based diets. This may seem surprising, but the protein and oil in distillers grains are concentrated, and both have more energy than starch. In forage-based diets, dry distillers grains have equal feeding value of the wet product (on a dry matter basis), but dry distillers may be easier to store.

If a high-starch supplement, like corn, is fed with very-low-quality forage, supplemental protein is likely to be needed as well. While there are several protein commodities available, alfalfa hay can serve well as a protein source in this situation.

Another difference between corn and corn distillers grains is the crude protein (CP) content. Corn is roughly 10% CP, while distillers grains have 30% CP. Therefore, distillers grains are commonly used as a protein source, and at times as an additional energy source. Corn is not a good protein source, particularly in low-quality forage diets.

With cheaper corn prices, corn may be used as a pasture supplement, but may need to be fed in combination with a protein source. Producers need to evaluate the price of acquiring, storing and delivering supplements, as well as the expected cattle performance to determine if supplementation is needed — and what commodity choices make the most sense.

Jenkins is a cow-calf and range management specialist with University of Nebraska Extension.

Source: UNL BeefWatch