Sheep producers have been urged to drench lambs at weaning this year, with unusually high reports of worm burdens and subsequent scouring in flocks from the medium and high rainfall regions.
The long period of low food on offer during winter combined with late seasonal rainfall has led to pastures with heavy worm contamination.
Department of Primary Industries and Regional Development veterinary officer, Danny Roberts, said it was imperative to wean lambs 14 weeks after the start of lambing to reduce the chance of deaths and ill thrift from scour worms this spring.
“Lambs will need an effective treatment at weaning and then, ideally, go onto a lower worm burden paddock to reduce the risk of further scouring and reduced growth rates,” he said.
“As lambs have no immunity to worms, it is also important to do a worm egg count four weeks after weaning to detect if significant amounts of scour worm are present, which could further reduce weaners’ growth rates over spring.”
Dr Roberts said there had also been reports of ewes, particularly those in poorer condition than normal, compromised by scour worms.
“These ewes may require a drench at weaning to help them through,” he said.
Recent department worm tests of ewes and lambs have confirmed high levels of scour worms, including black scour worm, brown stomach worm and, to a lesser extent, the thin-necked intestinal worm and large mouthed bowel worm.
Dr Roberts encouraged growers to undertake a drench resistance test, to ensure their drenching program was effective, particularly for brown stomach worm.
“The best way to test several drench types at the same time is to undertake a drench resistance test on lambs at weaning, which will require advice from a professional worm egg count service provider,” he said.
As the weather warms up, Dr Roberts advised sheep producers to regularly monitor their flocks for signs of scouring and to treat affected stock promptly.
“Any sheep with diarrhoea is also at risk of fly strike,” he said. “Producers could consider using a long acting preventative fly treatment, which can offer between three and five months of protection.”
Internal parasites cost the Australian sheep industry an estimated $369 million a year in mortalities, lost production and control costs.
Producers are reminded to be aware of chemical with holding periods when attending to fly strike and to use the department’s revamped free Flystrike Assist app to manage and record treatment applications.
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