HORSE owners are being advised by the NSW Department of Primary Industries (NSW DPI) to avoid grazing their horses in paddocks heavily infested with Paterson’s curse.
NSW DPI veterinary officer Robert Barwell said Paterson’s curse, which is sometimes called Salvation Jane or Riverina bluebell, is poisonous to livestock and can cause irreversible liver damage and in extreme cases, death.
“Horses are selective grazers that avoid eating Paterson’s curse when other pasture species are available, but at this time of the year when the weed is flourishing and can dominate paddocks, they may have little choice,” he said.
“Many people don’t even realise that they have a heavy Paterson’s curse infestation until the purple flowers bloom.
“This is the time of year when you need to look closely at the pasture your horses are grazing and if there is a heavy infestation of Paterson’s curse, take steps to prevent poisoning.
“The best way is to move horses to clean pasture, but if this is not possible, you need to provide sufficient fodder to sustain them until the threat from Paterson’s curse has passed.”
Dr Barwell said all species of livestock are potentially at risk, but horses and pigs are most susceptible.
“Horses lack the protection given by micro-organisms found in the rumens of sheep and cattle that can break down the toxic chemicals,” he said.
“Unfortunately, once you notice that a horse is affected the liver is severely damaged, so that even if removed from the weed, the horse will often die.
“Last spring a horse at Leeton had to be put down because it was so badly affected. “Even if a horse appears normal, slight liver damage may still be adversely affecting its performance.
“If the liver is damaged, it can mean treatment such as worming preparations that are normally broken down by the liver, become more toxic.”
Prolonged exposure can cause a gradual loss of condition over four to six weeks, followed by listlessness and poor appetite.
“Some horses show nervous signs such as head pressing, blindness and aimless wandering,” Dr Barwell said.
“These signs may not appear until after grazing the weed has ceased, so you may not realise the connection.
“Your local agronomist or Council Weeds Officer can provide advice on how to control Paterson’s curse and further information on the weed is available at www.dpi.nsw.gov.au/weeds .”
