Nitrate Poisoning Can Be Deadly

Nutrition Update
Volume 9 No.2, August 1998

A Hamiota cow-calf producer lost seven out of 65 cows last March due to nitrate poisoning. The nitrate levels in the greenfeed were the highest ever seen in the province.

Cows had been fed oat greenfeed all winter. Spot testing earlier in the fall showed trace levels of nitrates. In late March, the group of 65 cows with calves at foot, were fed some of the eight remaining greenfeed bales at 3:00pm. Cows were checked at 7:30pm and everything looked fine. By midnight, when the cows were checked again, seven cows were dead. An initial diagnosis of nitrate poisoning was made and spot testing of the greenfeed was done by John Patterson. The sample immediately turned black. The results from Norwest Labs showed a potassium nitrate (KNO₃) level of 7.68%. Half of the remaining bales were subsequently sampled to verify this result and results of 7.12%, 7.88% and 7.79% KNO₃, on a dry matter basis, were reported. The maximum recommended level of KNO₃ in ration dry matter is 0.8%.

Although nitrate poisoning does not occur frequently, the results are often catastrophic as it usually results in a high mortality rate. The potential for nitrate toxicity increases significantly when plants are grown on heavily fertilized fields.

 

For More Information contact your Local Specialist or MAFRI GO Teams Office or Centre.