Nitrates found in lambsquarter

Nitrates are an issue to be aware of with our annual forage like hay barley and other small grain that we make into hay. Moisture has not been universal across the landscape and some crops and weeds may be stressed, accumulating nitrate.

One early test of lambsquarter (see photo below) showed presence of nitrate. In large quantities, this weed could be a problem in hay. Taking a sample of the plant and bring it to the Extension Office ahead of haying can screen for the presence of nitrate. Also cutting forage in the afternoon allows for nitrates, which pool in the base of the plant at night, to move more uniformly throughout the plant. With drying conditions crops may be less likely to change nitrate status due to lack of moisture. Thus, forage quality is lost when bottom leaves of hay barley start to drop. Managers need to make a judgement decision between nitrate levels and hay quality. Forages already cut and, in a windrow, may need a lab analysis to determine levels of nitrate.

Nitrate toxicity:

Nitrate itself is not toxic to animals, but at elevated levels, it can cause a noninfectious disease called nitrite poisoning. Nitrate normally found in forage consumed by ruminant animals is broken down to nitrite (NO2) and then to ammonia (NH3). The ammonia is then converted to protein by microbes in the rumen (second compartment of the ruminant stomach). Ruminant animals with high nitrate levels in their diets accumulate nitrite. Nitrite is absorbed into the blood and combines with hemoglobin to form methemoglobin, which causes a reduction in the ability of the blood to carry oxygen from the lungs to body tissues. When the blood can no longer supply oxygen to the body, the animal can suffocate.

If you have questions about nitrates in forage, call the Extension Office at 406-654-2543.