December 14, 2007

Will you be feeding cane, millet, or oat hay 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, the nitrates may be excreted or bacteria in the rumen can convert them into microbial protein; however, at high levels, they can sicken or kill a cow.

Some plants are much more likely to be high in nitrates than others. These include cane, millet, and oats and weeds such as pigweed, kochia and lambsquarter. If your hay has lots of these weeds or is an annual grass, be alert to potential problems.

That doesn't mean these feeds always are toxic, nor does it mean that high-nitrate hay can't be fed safely, but always have these feeds tested in a lab to determine their safety.

There are many ways to feed high nitrate hay safely, including diluting it with grain or low nitrate forages. Frequent, small meals that slowly increase the amount of nitrate fed helps cattle adapt to high nitrate hay. Also be sure that cattle have plenty of clean, low nitrate water at all times.

Often nitrates cause cattle deaths after a snow storm has prevented cattle from eating naturally for a day or more. Avoid feeding high or even marginally high nitrate hay then because cattle will eat an extra large meal when very hungry, possibly overloading the nitrates in their system.

For further information see the UNL Extension NebGuide, Nitrates in Livestock Feeding (G1779).

Bruce Anderson
Extension Forage Specialist