Summer rain brings disease

By Andy Wilson

Dec 13, 2024

Livestock farmers are urged to be on the lookout after recent rain for barber’s pole worm — which can kill alpacas such as this championship female who died two years ago — and fly strike in sheep.

Agriculture Victoria is urging farmers to be vigilant with monitoring their livestock for signs of disease typically brought about by summer rain.

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Recent rain and humid weather have provided ideal conditions for a ‘suite’ of issues that can impact animal health, including barber’s pole worm, fly strike and an increase in toxic weeds.

Agriculture Victoria senior veterinary officer Jeff Cave said warm humid conditions caused barber’s pole worm eggs to hatch into larvae which could then be consumed by grazing sheep.

“Barber’s pole worm is a potentially harmful roundworm parasite of sheep that sucks blood from the lining of the stomach, causing anaemia,” Dr Cave said.

“Often the sheep go from looking fat and healthy to dead very quickly with few symptoms.

“The adult female worms are prolific egg producers, leading rapidly to heavy pasture contamination.”

Dr Cave said drench resistance to barber’s pole worm was becoming increasingly common, as with other internal parasites.

“Producers need to look out for sheep going down during mustering with pale eyelids and gums.

“Sheep don’t scour with barber’s pole worm as they do with other worm burdens — often the first sign is sheep dying.”

The worm’s lifecycle is about 21 days, so farmers are being urged to look for clinical signs around three to six weeks after summer rain and to have faecal egg counts done.

Barber’s pole worm outbreaks can lead to high mortalities in a short space of time.

Dr Cave said flystrike was also a major problem in humid conditions and needed to be identified and treated swiftly.

“If a fly-struck sheep is found, the affected area should be immediately treated by clipping close to the skin, (dressing) to prevent a re-strike, and the sheep should be moved to a hospital paddock to reduce the risk to the rest of the flock,” he said.

“Any maggots should be collected and killed to help reduce the build-up of fly numbers.”

Dr Cave also warned of the toxic weeds heliotrope (Heliotropium spp.) and panic grass (Panicum spp.) which thrive with high summer rainfall and can cause liver damage.

Lambs are particularly vulnerable to panic grass toxicity.

“The best prevention is to avoid grazing risky paddocks,” he said.

“If this isn’t possible, never put hungry sheep straight out onto risky pastures, but give them a good feed of hay first.”

For further information on flystrike, farmers are advised to contact their veterinarian or Agriculture Victoria or visit: flyboss.com.au/ and wool.com/sheep/welfare/breech-flystrike/