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Supplementing and Stretching Forage Resources

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Last update: February 2018

During periods of limited forage supplies, managing these resources to best meet animal requirements is one of the most important things a cow-calf producer can do. It is critical that producers evaluate the best way to supplement and stretch their forage resources during drought to remain viable in this industry.

Supplementing Forage Resources

Step 1: The first step in developing a feeding strategy is to determine the herd's nutrient requirements.

Table 1 shows the estimated dry matter intake and nutrient requirements for gestating and lactating beef cows. Age, weight, milk production, stage of gestation, current body condition and weather will all affect the requirements of a cow. This information is valuable when designing a low cost supplementation strategy, especially when feed and hay prices are high.

Table 1.

Step 2: The next step is to determine what nutrients are available in the forage.

This can be accomplished by collecting a sample of the standing forage or, if standing forage is not available, by testing the hay. This is very important because both standing forage and hay quality can vary greatly. In addition, many producers buy hay from unknown sources and other states and may not be familiar with the types of grass they are purchasing.

Step 3: The last step is to develop a strategy that will provide the nutrients needed at the lowest cost.

This can be complicated, but there is a logical approach. First, determine how many cows will be kept. Use this number and pasture measurements to determine your reserve herd days for all standing forage. A calculator to assist with this can be found at noble.org/tools. Next, decide if enough hay can be purchased to meet forage needs. If not, adjust cow numbers accordingly.

Compare the results from the standing forage test to the requirements of the cattle grazing it. This difference will determine what nutrients are needed and, therefore, the best supplement. Typically, standing native grass will be deficient in protein when trying to utilize as much forage as possible. Providing a high protein supplement will increase forage intake and should only be used if forage quantity is not limiting. Depending on the analysis of the forage, it is possible that the standing forage can provide all nutrients needed, especially for first trimester dry cows when calves have been early weaned. This is why it is so important to have the forage analyzed.

After the standing forage is used, compare the results from each hay test to the requirements of the herd. The difference will determine if a supplement is needed and, if so, if it will need to provide protein, energy or perhaps both. The lowest quality forage should be fed first because nutrient requirements will increase as gestation progresses and again when lactation begins. It is likely that each hay sample will need a different supplement. Changing the supplement each time may not be logistically feasible, so use the hay that is most limiting in nutrients to choose a supplement.

feedWhen forage resources are limiting, one option is to supplement with feed. By-products are usually the most economical feed choice. Examples include (clockwise from top left): corn gluten feed (CGF), wheat middlings (WMD), soybean hulls (SBH), barley malt sprout pellets (BMP) and dried distillers grains (DDG).

Stretching Forage Resources

When forage resources are limiting, it is important to stretch them as far as possible. Limiting access to hay and limit-feeding a supplement are two management strategies that can extend forage use.

Option 1: Limit Access to Hay

Depending on the quality of the hay, limiting access to hay for a period of time during the day will significantly reduce intake and waste. Research from the University of Minnesota showed that reducing access to hay for six hours per day reduced intake 22 percent. It also reduced waste from 7.7 percent to 0.8 percent while maintaining cow body weight. This strategy requires good quality hay (>9 percent CP, >55 percent TDN) to be successful.

Option 2: Provide a Feed Supplement

Another option is to supply a feed source as a substitute for forage intake. Before purchasing feed, be sure this makes economic sense. Usually, this is the most expensive option. Byproducts are typically the most economical choice for supplementation, but use of these feeds will depend on availability, storage and other variables unique to each producer's operation. Each of these products may also require special management considerations such as sulfur content or feed processing that must be taken into account.

Some examples of feeds that will stretch pastures include soyhulls, cottonseed hulls, peanut hulls, corn gluten feed, wheat midds, barley malt sprouts and dried distillers' grains. Concentrate feeds such as corn, wheat, oats and milo are also options, but should be used with caution. High levels of starch will decrease fiber digestion and may cause digestive and metabolic disorders.

Each of these supplements has different nutrient compositions and may need to be used in combination to make up for deficiencies in the forage. Average nutrient values for different types of forages and feeds can be found at nobleapps.noble.org/feedlibrary. Keep in mind that these values are averages and nutrient composition will vary between loads.

When employing a limit-feeding strategy, a higher level of management is required. Be sure to seek the advice of a livestock nutritionist. For more information, contact one of the Noble Research Institute's livestock consultants or your local extension agent.

Deke Alkire, Ph.D.
Former Ag Consultant