Heliotrope thrives on bare ground, such as along roadsides, fallowed ground and amongst stubbles.

This annual herb contains toxins known as pyrrolizidine alkaloids that damage livestock's liver.

Livestock tends to avoid eating heliotrope if other feed is available because heliotrope is relatively unpalatable. Sheep are primarily affected because they are most often grazed in the locations where heliotrope is commonly found.

British breed and crossbred sheep are more commonly affected than Merinos due to their different grazing habits.

The toxin found in heliotrope alters the liver's metabolism for copper causing the liver to hold abnormally high levels of copper.

The liver damage caused by heliotrope is cumulative, in other words, the liver damage increases each time an animal eats heliotrope.

When the liver becomes saturated with copper there is a rapid release of copper leading to kidney failure and death due to a condition commonly known as yellows.

Yellows usually does not occur until sheep have been exposed to heliotrope for more than one summer.

Yellows often occurs after the exposure to heliotrope has gone and when sheep are later put on lush pastures which are rich in copper, such as clover.

Other livestock is also susceptible to the effects of heliotrope, in fact, cattle and horses are more susceptible to the effects of the toxin found in heliotrope than sheep.

Unlike sheep, the signs of liver damage associated with heliotrope poisoning often occur as soon as cattle and horses are exposed, and large losses of stock occasionally occur.

For more information go to the Agriculture Victoria website or contact your local veterinarian.