WITH the ongoing drought and dry seasonal conditions there is a heightened risk of nitrate poisoning in livestock.
When an animal is poisoned by nitrate, the ability of its blood to transport oxygen is reduced.
As a result, an affected animal will have difficulty breathing, followed by becoming weak and staggery, before collapsing and dying. If clinical signs are noticed early enough, veterinary treatment is possible.
A range of different weeds, crops and pasture plants have been associated with nitrate poisoning.
Capeweed, variegated thistle, marshmallow and pigweed are well-known accumulators.
Other crop plants including maize, rape, soybean, linseed, sorghum, millet, wheat, oats and barley have also been associated with nitrate poisoning, under certain growing conditions.
The factors that typically lead to plants causing nitrate poisoning include:
• rapid plant uptake of soil nitrate following rain after a prolonged dry spell
• moisture stress and low temperatures
• the use of nitrogenous fertilisers
• spraying with hormone-type herbicides such as 2,4-D makes plants more palatable.
If you have any concerns, it is recommended that hay and other feed be tested prior to feeding to determine its nitrate levels.
Cattle and sheep can tolerate a certain amount of nitrate.
One way of reducing the risk of nitrate poisoning is to ensure that cattle and sheep aren’t overly hungry when introduced to a new feed, so their intake of nitrate is moderated to a tolerable level.
If nitrate poisoning is suspected, animals should be removed without delay from the suspect paddock/feed and placed onto low-risk feed containing less toxic herbage.
For further advice please contact your local veterinarian or Agriculture Victoria veterinary or animal health officer.
For more information about managing during drought and dry seasonal conditions go to agriculture.vic.gov.au/dryseasons or call 136 186.