by Mary Drewnoski, University of Nebraska Extension

Veterinary toxicologists in the region are again seeing cases of cattle deaths associated with water hauled in tanks or equipment previously used for fertilizer. Recent cases submitted to the Iowa State University Veterinary Diagnostic Laboratory have included substantial death losses.

This is not a new problem, but it is one worth repeating because the consequences can be severe.

Tanks and equipment that have been used to haul urea- or nitrate-based fertilizers should not be used to transport drinking water for cattle even if they have been thoroughly washed.

A separate water tank costs far less than losing cattle.

It is very difficult to ensure that all fertilizer residue has been removed. Plastic tanks are not the only concern; steel tanks and other equipment, including hoses, that have been used with fertilizer can also pose a risk.

Why is the risk so high?

Any nitrogen fertilizer remaining in a tank can potentially cause nitrate or urea toxicosis in cattle, depending on the fertilizer source.

Ruminants are particularly susceptible because of the way nitrate and urea are metabolized in the rumen. Poisoning can occur rapidly and may result in death.

Nitrate-contaminated water is particularly concerning. Cattle can be poisoned by a lower amount of nitrate when it is consumed in water than when the same nitrate is consumed in forage.