As we approach fall, there becomes a higher risk of frost at night. Frost is one of the disruptions to normal plant growth that can cause a buildup of nitrates in forages and cause nitrate toxicity in livestock. Other disruptions that can cause nitrate buildup can include hail, spray drift, or drought.
These unfavourable conditions cause issues because when they occur, it can cause nitrates to buildup in the plant instead of being converted to ammonia. Having excess nitrates means that the carrying capacity of blood to carry oxygen is decreased and animals can die due to this lack of oxygen in the blood.
Signs of nitrate poisoning may include muscle tremors, frothing at the mouth, weakness, diarrhea, difficulty breathing, and death in as soon as 3-4 hours. Nitrates can cause lack of appetite, slow growth, abortions, and reduce milk production.
Crops that are more susceptible to nitrate build-up include cereals such as barley, wheat, and oats, as well as sorghum and corn, among other crops. Nitrate build-up in alfalfa or alfalfa-brome stands is less of a concern.
Some ways to prevent nitrate poisoning are to:
1. Feed test to make sure you know what is in your feed.
2. Mix high nitrate forage with low nitrate forages to safely transition animals to slightly higher nitrate forages.3. Make sure your ration is balanced for your herd.