In last month’s issue we discussed the metabolizable protein (MP) system and how it separates the protein and nitrogen needs of the beef animal from the microbes that live within their rumen. In the past, it has been easy to meet the animals rumen undegradable protein (RUP) needs using corn-based by-products. However, due to drought, energy prices, or other factors, corn-based by-products may become in short supply or simply high-priced.

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Ration Formulation and By-products

When we look at distillers grains as the primary protein source we can meet MP needs without adding urea due to recycling of urea within the animal (Table 1). When distillers grains are high priced it is tempting to remove all of the distillers grains and simply feed urea as a cheap protein source. However, a summary of experiments determined that a small inclusion of distillers grains or gluten in the ration (10% on dry-matter basis) has the largest return on investment when combined with urea. When we remove distillers or gluten from the ration, there is typically a reduction in average daily gain. This reduction of gain is approximately 0.35 lbs when we switch from a distillers ration to a corn plus urea ration in finishing diets. The reduction in average daily gain is not as large when we keep a small proportion of distillers grains in the ration at 10% (dry-matter) and include some urea (0.15 lbs average daily gain reduction). When profitability and animal performance are considered, that small amount of distillers more than pays for itself, even at high prices. These examples are specific to finishing cattle and there is typically a greater need for RUP in growing rations. We will help you to evaluate these changes in your operation for protein and discuss some important management adjustments when feeding less by-products.

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Practical Application of Finishing Rations Without By-Product Feeds

Many of us have recently faced a situation where using by-product feeds is simply not an option, regardless of economics. As a result, many of our clients have shifted back to using urea-based supplements, soybean meal, whole soybeans, or other protein sources. Ration composition changed dramatically, mostly over the course of a few steps, and has reminded many cattle feeders of some other factors one must consider when feeding without by-products.

First, roughage quality becomes a much larger factor in rations without wet by-products. In the past, many of us relied on corn stover, wheat straw, or other low-quality forage sources because of the availability of wet by-products. In drier rations, our options are more limited; and high-quality forages are needed. We have been able to maintain 1-2% corn stover (dry matter basis) in many of these finishing rations, and slightly more in some of the grower and cow rations, but we must have a more palatable roughage source to round out the ration. Alfalfa hay or silage fits these rations well because of the protein it provides. Corn silage is a good option, as are small-grain silages. However, in step-up, growing, or cow rations you simply have to have greater palatability and quality of forage that we often utilized with wet by-products. To that end, we are encouraging people to really focus on harvesting quality forages this summer to provide versatility in rations for fall and winter.

Second, and perhaps more important in finishing rations, is that removing by-product feeds results in higher corn inclusion, thus a greater proportion of energy in those rations is fermented at a similar rate. This results in more potential for acidosis and bloat in rations lacking by-products, assuming similar roughage inclusion. Rations containing mostly high moisture corn can be especially problematic because it is fermented rapidly and to a great extent in the rumen. Practically speaking, it makes the most sense to utilize a combination of corn processing methods and perhaps more roughage in rations without by-products.

Bunk management is more important, and requires greater precision in rations that do not include by-products. Because bloat is more common, an increase in moisture in hay or silage piles due to rain or variability in source results in a greater likelihood of losing cattle. Furthermore, cattle tend to give the bunk reader less “warning” when they are nearing peak intake and it is easier to surpass their desired level of feed. Consistency of feeding time, accuracy of ingredient loading, correctly mixing, and uniformly delivering feed become even more important in rations with no by-products.

Feeding cattle in the absence of by-products may be a reality at your operation now, and will likely become a reality for most of us at some point in the future. While it is different, it is not new, and should not be scary. Understand what kind of protein you need, focus on high-quality roughage sources and dial in your bunk management to ensure your cost of gain is competitive. If we can be of assistance, please get in contact with us.

In Summary:

• In lower energy (growing) rations less RDP is needed to support microbes degrading forage, however higher energy (finishing) rations, urea is an option to meet protein needs.

• Focus on forage quality this season to be prepared for lower by-product inclusion

• Ration management with high starch, low by-product rations is crucial. Bunk management and mixing accuracy are more important than ever

• There is more to distillers pricing than meets the eye, even at higher prices, a low inclusion of distillers may be warranted to preserve animal performance

Great Plains Livestock Consulting is available to help you with any of your nutrition-related needs. They can be reached at gplc-inc.com.