Testing forages should pay dividends
August 22, 2008
Forages for winter feed will be in short supply in many areas of North Dakota that experienced moderate to severe drought during the 2008 growing season.
That shortage will create emergency situations in which livestock producers will use nontraditional feedstuffs and hay from Conservation Reserve Program (CRP) lands as a substantial portion of the ration for their animals. However, some of these forages may be low in nutritional value and high in nitrate, resulting in livestock that are undernourished or at risk of being poisoned by nitrate.
Having the forages tested is the best way for producers to know the quality of feed their livestock is consuming, according to Kevin Sedivec, North Dakota State University Extension Service rangeland specialist, and Greg Lardy, NDSU Extension beef cattle specialist.
Emergency forages with the potential for nitrate toxicity include small grains such as wheat, barley and oats; late-season crops such as corn and sunflowers; and weeds such as kochia and pigeongrass. Small grains that were planted for grain but harvested for hay due to drought stress conditions will have a greater risk for toxic levels of nitrates.
Sedivec suggests producers collect a core sample from three to five bales from each field and send them to a reputable laboratory for nitrate level testing. NDSU publication V-839, “Nitrate Poisoning of Livestock,” will help producers interpret the test results. The publication is available online at http://www.ag.ndsu.edu/pubs/ansci/livestoc/v839.pdf. Producers who have high nitrate levels should visit with their local county Extension agent for recommendations on feeding high-nitrate feeds.
Lardy says predicting the nutritive value of other emergency forages, such as hay cut on CRP wildlife land, as well as crop residues such as corn stalks, is difficult without utilizing the services of a qualified nutrition laboratory. Using book values for these types of forages can lead to erroneous conclusions about forage quality. He strongly encourages livestock producers to test these feeds for nutritional components and, if pertinent, nitrate levels.
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Certain CRP lands in the region were eligible for haying beginning Aug. 2. Nutritional quality can vary dramatically with CRP hay. Nutritive quality depends on when the field was last hayed or grazed, timing of haying relative to forage maturity and the proportion of alfalfa to grass, as well as precipitation.
In many cases, much of the hay from CRP and wildlife lands harvested in August will be deficient in protein and energy for most classes of livestock, the NDSU specialists warn. Minerals and vitamins, especially Vitamin A, also can be deficient. Producers should have their hay tested for protein, energy, calcium, phosphorus and Vitamin A.
CRP hay, as well as most grass-dominant hays, harvested in August will have a crude protein value of less than seven percent and digestibility value of less than 50 percent. However, if the CRP or hay field was green when harvested or contained greater than 30 percent alfalfa, nutritional quality can approach nine percent to 11 percent crude protein and digestibility greater than 55 percent. If the field was brown and dry, crude protein can be as low as five percent and digestibility less than 45 percent. If the CRP field has not been cut for three or more years and standing litter is high, nutritional quality will be well below the needs of all classes of livestock.
Testing forages will allow management decisions that improve livestock productivity, as well as improve overall profitability of the ranching operation, the specialists say. They add that producers should implement feed supplementation programs if the nutritive value of their forage supply is low to balance the ration and ensure healthy, productive livestock.
More information on forage quality is avilable in NDSU Extension publication AS-1251, “Interpreting Composition and Determining Market Value.” It’s online at http://www.ag.ndsu.edu/pubs/ansci/dairy/as1251w.htm.