Persistent drought conditions in Wyoming have increased the likelihood farm and ranch livestock could be affected by eating forages that accumulate nitrates during prolonged hot, dry periods.
University of Wyoming Beef Extension Specialist Steve Paisley says livestock producers should sample and test forages for nitrates during prolonged droughts.
"To properly sample forages, producers will need a hay probe to not only test the outside of the bales or stacks, but the inside as well," he says.
"A minimum of 10 bales from a susceptible field needs to be sampled to get an accurate test. Nearly every county extension office, local co-op or feed store should have a forage probe available for ranchers.
"The samples can be placed in a sealable bag and sent to commercial feed testing labs such as Ward Laboratories or SDK Laboratories."
Samples can also be sent to the Wyoming Department of Agriculture's Analytical Services Lab at 1174 Snowy Road in Laramie, Wyo. For more information, call the lab at (307) 742-2984.
Some plants are more likely to accumulate nitrate than others, according to Paisley. Crops capable of high levels of nitrate accumulation under adverse conditions such as drought include corn, small grains, Sudan grass and sorghum. Weeds capable of nitrate accumulation include pigweed, lambsquarter, sunflower and bindweed.
"Nitrate levels of less than 3,000 parts per million are considered safe, but forages with levels between 3,000 and 6,000 ppm require special feeding considerations to improve feeding safely," he says.
"Nitrate levels more than 9,000 ppm are considered potentially toxic and should not be fed as the only source of food."
Information to help ranchers is available on line at www.uwyo.edu/ces. Producers can check a UW bulletin, "Water Quality for Wyoming Livestock and Wildlife," at the site by clicking on "Search Bulletins," and enter "B-1183" in the Publication Number field. Once opened, scroll down to page 25, chapter six, on "Nitrate and Nitrite."