Plants vary between 10cm and 30cm in height and have a reddish-brown central stalk with a bright green fern leaf.
Central West Local Land Services is urging livestock owners to be on the lookout for rock or bracken fern in their grazing paddocks, which can cause toxicity.
Found in many parts of the Central West region, rock fern is a hardy plant that survives dry conditions and reshoots readily after rain in autumn and winter.
These fronds are particularly toxic to cattle, and less commonly sheep. While not overly palatable, stock will consume rock fern when feed is limited, or they may ingest it incidentally when the plant is present amongst short green, or dry standing feed.
Hungry, young and naïve stock are most at risk.
Nik Cronin Central West Local Land Services District Veterinarian said, “The prolonged dry following summer, and the late autumn break have provided ideal conditions for rock fern.
“The movements of young trade cattle, as well as the influx of cattle from droughtaffected areas into our region have also increased the risk. Our records show that cases most commonly occur in the months of May-July, peaking to a high in June.
“Two cases have recently been diagnosed in the last week within the Central West Local Land Services region – one case in agistment cattle near Narromine with 6 out of 48 animals affected – 4 deaths, and the other in trade weaners at Coonabarabran with 14 out of 34 affected – 3 dead.
“For now we would recommend that producers check grazing paddocks for rock fern. If rock fern is present where stock are grazing then they should be removed” Nik said.
If you have deaths or signs of toxicity in your livestock, please call your veterinarian.