24 September 2007

6 minute read

The wet version may have greater energy than the dry product. This is due some of the volatile compounds escaping during the drying process. Distillers grains can be sold without solubles but it appears that the most prevalent form sold includes the solubles. Some processing plants market modified wet distillers grains plus solubles (50% dry matter).

Distillers grains (wet or dry; with or without solubles) can be fed at 10 to 15% of the diet (DM basis) as mainly a source of supplemental protein. Dry Distillers Grains with Solubles has an apparent energy value equal to corn grain when fed to finishing cattle at levels ranging from 10 to 20% of total ration dry matter. Feed cost of gain will be reduced if the cost of Dry Distillers Grains with Solubles is not greater than cost of corn grain on a dry basis. At these relatively lower levels you will not be creating much excess phosphorus or nitrogen in the manure.

When fed at levels higher than 15% of the diet, distillers grains is still a source of protein but also its energy content has more impact. To feed a 700-lb steer consuming 18 lb of dry matter, a ration containing 20% distiller's grains would equate to 4 pounds of Dry Distillers Grains with Solubles or approximately 12 pounds of Wet Distillers Grains with Solubles. Most research data indicates the optimum level of wet distillers grains is 25% or less of the diet dry matter.

The actual range of inclusion is around 10-40% of the diet dry matter. The nutritional content of the distillers becomes more critical at the higher levels. In some studies, feeding at 40% of the diet dry matter has decreased performance and efficiency of gain and/or decreased carcass quality when compared to lower levels. At these higher levels you would want to more closely track manure composition for levels of phosphorus and nitrogen. You will be more likely be feeding these to excess.

You can easily feed 4 pounds of distillers grains to a beef cow and certainly even more if you take into account some of the considerations listed below. Feeding distiller's grains may provide enough phosphorus to allow supplemental phosphorus sources to be removed from mineral packages for cattle consuming forage-based diets. Admittedly, there has not been as much work with animals on forage-based diets as compared to feedlot diets. A creep grain mix may well be able to be comprised of 50% Dried Distillers Grains with solulbles (notice this is not 50% of the calf's total diet).

Distillers grains are generally low in calcium, high in potassium, phosphorus and sulfur. Feeders should reduce or eliminate supplemental phosphorus, potassium and sulfur when high levels of these byproducts are fed.

To maintain performance and to avoid urinary calculi (water belly), Calcium to Phosphorus ratios should be equal to or greater than 1.2:1 but not greater than 7:1. Supplemental calcium is commonly supplemented as limestone.

Excess dietary S can be a problem for ruminants for two reasons. First, high levels of sulfur (above 0.4% of diet dry matter) from feed and water can lead to polioencephalomalacia (PEM), or "brainers." Excellent bunk management so as to reduce the potential for acidosis will assist in reducing the incidence of PEM. A second option may be feeding higher levels of thiamine to combat PEM.

Sulfur interferes with copper absorption/metabolism. Regions with suspected high sulfate in the water may want to get the water tested. Producers may need to feed elevated levels of copper if ethanol products will be fed for an extend amount of time.

In the table below, examples of distillers grains with solubles were created having a sulfur content of .60, .80, and 1.0% sulfur content and its impact on a corn-corn silage diet at different levels of inclusion. Notice there are several situations where we are close or over the suggested maximum level of sulfur in the diet.

Cattle don't handle fat as well as we do. Generally, we try to hold the fat content of cattle diets to a maximum of about 5%. Dried Distillers Grains with Solubles can range from 8 to as high as 12% in fat content.

The protein in distiller's grains is approximately 50% degraded in the rumen (Degraded Intake Protein, DIP) and 50% undegraded intake protein (UIP). UIP is commonly referred to as "escape or bypass protein." Escape protein is not fermented in the rumen but is digested by the animal in the small intestine. Supplements can be formulated to best meet UIP and DIP requirements; however, DDG or DDGS can serve as the sole protein source for cattle. When feeding DDG or DDGS as a sole protein source, it is important to remember that higher levels of crude protein must be fed to effectively meet the DIP requirements. A rule of thumb is that, to provide similar levels of DIP, it takes 2.7 lb of DDGS to replace 1 lb of 44% crude protein soybean meal.

Anytime you dry a feed there is a potential for altering nutritional availability. The sugars can undergo a chemical "browning reaction" that renders part of the carbohydrate and protein unavailable to the animal. This reaction is similar to that of wet hay that overheats.

Generally, dried distillers grains should have a bright, golden brown color and smell something like beer. If the product has been burnt, it will be darker and have a burnt molasses odor. Suppliers will often discount the price of a burnt product to account for the reduction in feed value. The lab analysis should include an analysis for heat damage or ADIN (acid detergent insoluble nitrogen) to assess the extent of protein damage. Since the ADIN value only represents nitrogen, it must be multiplied by 6.25 to calculate the appropriate protein value. The calculated protein value represents the amount of crude protein that is unavailable. For example, if a sample contains .9% ADIN, then the unavailable protein value is 5.625% (0.9 x 6.25). Thus, if the sample contains 30% crude protein, only 24.375% crude protein is available (30 - 5.625). The nutrient content of co-products produced by ethanol plants will vary between plants. Routine sampling and laboratory analysis is recommended in order to effectively use these feeds. Moisture level in the wet feeds does vary and a dry matter (moisture) analysis is one of the most important routine analyses to conduct.