Although the costs involved with mechanically harvesting high nitrate forages are significant, Krantz says there are livestock safety benefits to this approach.
"The ensiling process reduces nitrate levels making them much safer for consumption," he said. "However, it is not recommended to green chop these forages and let them heat overnight as this process favors the formation of nitrite which is even more toxic that nitrate."
Oats, corn and barley consistently have been documented as crops with the most potential to account for nitrate poisoning in livestock; however, Krantz says that annual forages such as sudangrass, sorghum-sudan hybrids and millets can be dangerous as well.
"Weather conditions may intensify the accumulation of nitrates in forages. Plants that survive an extended period of drought will experience increased levels of nitrates immediately following a rain as the parts of the plants begin to resume their growth. The nitrate levels will continue to increase for several days afterward," he said.
Quick nitrate testing is available at all SDSU Extension Regional Centers
Suspected crops may be brought to SDSU Extension Regional Centers for a preliminary test that only takes a few minutes. Although exact nitrate levels cannot be determined through this procedure, their presence can be determined. If and when nitrates are verified in the plant tissue, samples are then sent to a lab for further testing.
"If nitrates are not found, producers can be confident that the forage is safe for their livestock," Krantz said.
Water may be an additional source of nitrates for livestock whether consumption is from a dugout, dam or well. Krantz recommends producers obtain a livestock suitability analysis for water sources.
"This is especially important in areas where nitrate poisoning potential from crops is a concern," Krantz said.
Initial water tests for total dissolved solids can be accomplished at SDSU Extension Regional Centers. Depending on the levels recorded, further sampling at a lab may be required.