Fireweed

There are a few types of fireweed found in Australia, with majority of species being poisonous.
This plant is a short shrubby plant with yellow daisy like flower.

Cattle become affected if they are short of feed, or not used to having the plant in their environment. Sheep and goats seem to be more tolerant to the toxic effects and can be used to manage fireweed.

The most common is Senecio madagascariensis can cause liver disease when ingested. This is a slowly developing disease. Initially signs can be quite vague like:

lethargy
diarrhoea
general unwell appearance and behaviour

When liver function is affected enough, you will spot signs of jaundice – the usually white mucous membranes will appear yellow (the whites of the eyes, skin inside vulva etc.).
Cattle will become photosensitive and get sunburn on paler parts of their nose/mouth area, they can become dull and stagger with nervous signs.

There is no specific treatment, only supportive care which includes removing the animals from the pastures affected, putting on good quality hay and locking them up with shade and water.
Giving antibiotics can help prevent secondary diseases due to the ineffective liver.
If an animal has been acutely affected, treatment can also include binding agents such as bentonite, and giving vitamin B1 to help prevent neurological brain signs.

Unfortunately, pasture management involves treating the fireweed after the autumn rains with chemical treatments or physically removing the plants.
If you are physically removing the plants, make sure you wear gloves as it can be irritating to human skin.
Once there is any sign of a flower, we recommend introducing sheep or goats to the property to eat the plants, was the flowers indicate the presence of seeds, which can be further spread with physical removal. Please note, sheep and goats used to eat the plants but can’t be used for more than 2 seasons in a row and should be non breeding stock.

More information can be found on the DPI website: https://weeds.dpi.nsw.gov.au