Nitrate Toxicity

Toxic levels of nitrate in livestock feed can cause reduced production and poison unborn and mature animals, causing abortion or death. Normally, feed does not contain enough nitrate to make it toxic. However, when conditions interfere with the growing cycle, like drought, hail and frost, nitrate can accumulate in plants. Even then, forage from these plants can sometimes safely be fed to livestock, if proper precautions are taken. Knowing the level of nitrate in your feed is the first step in protecting your livestock from this problem. Further instructions on safely feeding forage under these conditions should be obtained from your extension service or other local authority.

Percent of Nitrate in feed sample
0.0 – 0.44 Considered safe to feed under all conditions
0.44 – 0.66 Safe for non-pregnant animals under all conditions. Limit for pregnant animals to 50 percent of the total dry matter in the ration.
0.66 – 0.88 Limit to 50 percent of the total dry matter in the ration.
0.88 – 1.54 Limit to 35-40 percent of the total dry matter in the ration.
1.54 – 1.76 Do not use for pregnant animals. Limit to 25 percent of the total dry matter in the ration.
1.76 – Up Do not feed. Feeds with over 1.76 percent nitrate are toxic.

The percentage above is expressed in percent of Nitrate (NO3). Other methods of expressing nitrate are Nitrate nitrogen (N) and Potassium nitrate (KNO3). Since each of these methods of expressing nitrate differ, nitrate amounts must be expressed in the same way before comparing or adding the amounts. The following formulas have been supplied to enable you to do convert all nitrate amounts to the same expression method. Select a nitrate expression method. Then, convert all other nitrate amounts into your selected expression method. For example, if your selected expression method is Nitrate (NO3), use the first two formulas to convert Nitrate nitrogen (N) and Potassium nitrate (KNO3) amounts into Nitrate (NO3) amounts.

Nitrate (NO3) = Nitrate nitrogen (N) multiplied by 4.4
Nitrate (NO3) = Potassium nitrate (KNO3) multiplied by 0.61
Nitrate nitrogen (N) = Potassium nitrate (KNO3) multiplied by 0.14
Nitrate nitrogen (N) = Nitrate (NO3) multiplied by 0.23
Potassium nitrate (KNO3) = Nitrate nitrogen (N) multiplied by 7.2
Potassium nitrate (KNO3) = Nitrate (NO3) multiplied by 1.63