While summer rain is helpful for pasture and crop growth, it also promotes the growth of toxic weeds.
Heliotrope, also known as potato weed, is one of the toxic weeds germinating following recent and sporadic rain in the south west.
Agriculture Victoria Meat and Wool Livestock Industry Development Officer Dr Hannah Manning said these plants flourish in degraded pastures after summer rain so the conditions have been perfect for weed growth.
'Heliotrope contains a toxin known as pyrrolizidine alkaloid that damages livestock's' liver, which is also the same toxin that is found in Paterson's curse,' Dr Manning said.
'Heliotrope is not tasty so stock tend to avoid it but if there is no other feed available, they will consume it.
'The damage that is done is cumulative, which means, the liver damage increases each time an animal eats heliotrope. This may lead to liver failure or impaired copper metabolism leading to a build-up of copper in the liver.
'All animals are susceptible to heliotrope poisoning.'
Signs of liver damage associated with heliotrope poisoning often occur soon after cattle and horses are exposed to heliotrope and large losses of stock occasionally occur.
Dr Manning said sheep are more affected by the chronic copper poisoning which can result in sudden death when stored copper is suddenly released from the liver leading to a haemorrhagic crisis.
'This can happen well after sheep have been exposed to Heliotrope.'
The control of heliotrope involves using a combination of pasture management, grazing management, cultivation, and chemical control, consult your pasture agronomist for advice.
