Dairy Cattle: Distillers Grains Can Contribute to Performance and Cost

Distillers grains can be a good protein supplement for dairy cattle.

The fact that distillers grains, either wet or dry, can make a valuable contribution to cattle diets, regardless of the animals’ stage of production, is well-established.

However, various factors need to be considered when determining their potential value in your dairy production system.

During the distillation process, the starch component of cereal grains (normally 60 percent to 70 percent) is fermented out of the grain to ethanol. By removing this fraction, the remaining nutrients are concentrated, roughly threefold. For ruminants, this can be beneficial, resulting in an affordable protein supplement containing roughly 30 percent crude protein. Also, after removal of the starch component and concentration of the fat and fiber fractions, distillers grains are a good source of energy in the form of digestible fiber and fat.

However, some of the nutrients that become elevated in distillers grains may limit their potential use in cattle diets. The phosphorus content (about 0.8 percent to 0.9 percent) of distillers grains may require the addition of more calcium to maintain a proper calcium-to-phosphorus ratio.

Excess phosphorus in the diet also will result in increased excretion in the manure and the associated need to dispose of this phosphorus.

The sulfur content of distillers grains (about 0.5 percent to 1.2 percent) may limit their potential use because excessive sulfur in the final diet may cause trace mineral imbalances, health problems, reduced intake and possibly death.

The fat content of distillers grains is beneficial to growing and lactating dairy cattle as a concentrated energy source. But excessive fat in the diet of forage-fed animals can reduce forage digestibility, resulting in lower net energy consumption and lost body condition.

One additional benefit of feeding distillers grains in the wet form is the conditioning factor this wet ingredient brings to an otherwise dry diet. This may stimulate consumption by growing and finishing cattle, particularly if all the other ingredients in the diet are dry and/or dusty. The moisture added helps tie the loose, fine particles together.

Conversely, dried distillers grains actually may contribute to the dustiness of an already dry diet because of the fine particle size. A dusty ration may not be palatable. This dustiness can be alleviated if even a small amount of some other wet ingredient, such as silage, is fed.

Handling is also an important consideration. Wet distillers grain stored outside during the summer is subject to spoilage within three to five days. If the operation is not large enough to use a full load within this brief time frame, the product can be stored in sealed plastic bags to limit oxygen content and potential for mold development. Another benefit of sealed storage may be to improve the opportunity to purchase an excess supply of wet distillers grain at a lower price.

Using dried distillers grains reduces the risk of spoilage, but because of dustiness, they cannot be stored long term outdoors. Also, because of their high fat content, dried distillers grains may bridge in a gravity-flow bin. Ideally, the dried product would be stored in a concrete-floored commodity bay.

Variability can and will be an issue when feeding either the wet or dry product. Particularly, the moisture level in wet distillers grains can vary greatly among loads, affecting the actual amount of dry matter fed. Also, nutrient content may fluctuate through time among loads and suppliers. Notable differences also can occur in nutrient content among distillers grains originating from corn, sorghum or blends of two or more grains.

In summary, factors to consider when formulating rations with distillers grains include protein, fat, phosphorus, sulfur, moisture and storage options. If these factors are optimized and rations are balanced properly, distillers grains can contribute to good production and even lower the cost of production for livestock producers.

By J.W. Schroeder, Dairy Specialist - NDSU Extension Service