As the federally mandated demand for ethanol continues to increase, production of corn by-products such as distillers grains continues to increase as well. Remember that about two-thirds of the corn bushels used in ethanol production are actually recovered as ethanol.The other third is the by-products that the cattle feeding industry has grown to love, due to the high level of energy and protein they can economically add to a diet in place of corn. 

When it comes to balancing beef cattle diets using distillers grains, there usually is a shortage, on paper at least, of degradable intake protein (DIP). DIP is needed in the rumen to feed bacteria so that they may continue to proliferate and take an active role in feed particle breakdown. These bacteria are living organisms themselves that need a constant supply of both protein and energy to survive. Because some fractions of protein in different feedstuffs are unavailable for breakdown in the rumen by these bacteria, it is important to balance diets making sure we have enough DIP for these bugs to continue to thrive.

Urea is an excellent source of DIP because it is easily broken down in the rumen and able to be utilized by rumen bacteria as a protein source. Conversely, dried distillers grains (DDG) typically contains only about 28% DIP, relatively low compared to the 45% usually found in corn. With these numbers, one would expect that we have a shortage of DIP when we replace corn in the diet with DDG. However, work that has been done by the University of Nebraska would suggest otherwise.

Heifers were finished using diets that contained either 10 or 20% DDG with and without added urea in this study. Both diets without added urea had calculated values that indicated a shortage of DIP in the diet. However, researchers found in this study that not adding urea to the diets had no negative effects on cattle performance or carcass characteristics. 

Performance measurements for finishing diets containing DDG with or without supplemental urea.


10% DDG

10% DDG + Urea

20% DDG

20% DDG + Urea

DMI, lb





ADG, lb










Source:  Degradable Intake Protein in Finishing Diets Containing Dried Distillers Grains; Vander Pol, et al.  2005

Furthermore, when blood was sampled for Blood Urea Nitrogen (BUN), all cattle in the trial showed a level present in their blood which was at least 50% above what is considered to be the minimum level of BUN needed to maintain optimum performance. This indicated that adequate DIP was provided to the rumen and cattle performance in this trial confirmed it.

Implications from this work could be beneficial for many cattle feeders. Typically urea has been used as a economical protein source for cattle. However in recent years with the higher costs of nitrogen, this is not so true anymore. With the addition of distillers grains to cattle diets in place of corn, we typically don’t need to supplement additional protein to meet the animal’s needs. Studies like this confirm that performance can still be maintained without the urea. It’s also good news for anybody that has had to beat their urea-containing supplements out of an overhead bin! 

For more information, visit Great Plains Livestock Consulting Inc.