Is nitrate poisoning on your radar?

At this time of year, nitrate poisoning should be on your radar. Nitrate toxicity occurs in fast-growing plants when nitrate is taken up faster than plants can use it. In the rumen, nitrate is changed to a form that stops red blood cells from carrying oxygen.

When nitrate levels get too high in feed, it can result in rapid death and abortions from lack of oxygen.

Several factors increase the risk of nitrate poisoning:

Fast-growing plants, where conditions have reduced photosynthesis. For example, low temperatures or low sunlight due to fog or being overcast
Following a drought, where high levels of nitrate have accumulated in paddocks
Application of nitrogen fertiliser
New grass paddocks and crops
Paddocks with heavy under-sowing

Nitrate poisoning is extremely dangerous. Often, the first sign seen is sudden death (multiple dead/ down cattle). This makes it vital to manage the risk.

New grass paddocks and crops should be tested during high-risk periods; first grazing periods often pose the highest risk. On farm nitrate kits are available from the clinic. These are a quick, easy and cheap way to test your pastures before putting stock on. This is the most effective way to control nitrate risk.

Feed cattle first to prevent stock from gorging themselves on pastures and crops. Check your animals a couple of hours after putting them on a new break. In higher-risk situations, only graze the paddock for 1-2 hours or defer it to a lower-risk period.

Symptoms of poisoning include staggering, fast breathing, muscle tremors, drooling and brown mucous membranes (vulva, gums and white of the eyes). Call your vet at the first sign of trouble; don’t wait until sudden death is a symptom. Remove all animals from the affected pasture. Treatment is usually expeditious and effective. However, abortions following poisoning are common.