Are you feeding cane, millet, oat hay or maybe cornstalk bales to your cows this winter? If so, don’t let high nitrate levels kill your cows or cause abortions.
Nitrates occur naturally in all forages. At low levels, nitrates either are converted into microbial protein by bacteria in the rumen or are excreted. But when nitrate concentrations get too high, they can cause issues.
When stress affects pasture and hay production, nitrates often reach potentially toxic levels. Some plants are more likely to be high in nitrates than others. Annual grasses like cane, millet, oats and even corn often have elevated nitrate levels—so do certain weeds like pigweed, Kochia and lambsquarter. If your hay has lots of these weeds or is an annual grass, be alert to the potential for high nitrates.
That doesn’t mean these feeds are always toxic, nor does it mean that high-nitrate hay can’t be fed safely. But always test these feeds for nitrates in a lab before feeding to determine how to feed them safely.
If we do have high nitrates, there are many ways to feed the hay safely. Diluting the hay with grain or low-nitrate forages is most common. Frequent, small meals that slowly increase the amount of nitrate fed help cattle adapt to high-nitrate hay.
Remember with this last approach that any time cattle go off feed and then come back, like after a snowstorm or if a feeding was missed, they are more likely to consume more hay than normal. This raises the amount of nitrate consumed and can result in poisoning, even in an adapted herd. Finally, make sure cattle have plenty of clean, low-nitrate water at all times.
Nitrate concerns are nothing to sneeze at, but with the right tools, they can be managed safely. Test hay you think may have an issue, especially annual grasses and hay with a high percentage of weeds. If tests come back high, plan to feed safely by dilution, or gradually increase the amount of the feed to adapt animals to it. — Ben Beckman, Nebraska Extension educator
