Warning on worm threat

Producers are facing an increasing threat of worm problems in sheep, goats and young cattle following the storm rains that fell across much of the State in recent weeks.

NSW Department of Primary Industries warned producers that heavy falls (more than 50 millimetres), coupled with warm conditions, have created the ideal environment for worm eggs to hatch.

State Worm Co-ordinator Stephen Love said, after a run of dry years in which the worm burden was reduced, producers can expect a rapid increase in the numbers with the return of favourable conditions.

“The main threats for sheep and goats come from the roundworms barber's pole worm, small brown stomach worm and black scour worm, with barber's pole worm being a particular threat in northern NSW,” Dr Love said.

“Already there are reports of problems with barber's pole worm in the northern and central tablelands and that’s likely to be the tip of the iceberg.

“For all these worms, the most important thing to do under current conditions is to step up worm egg count monitoring to see if animals need drenching.

“Drench with an effective drench and move stock, if possible, to pasture that has not been grazed by goats or young sheep in recent months.”

Some producers will get worm problems reappearing soon after drenching and the most likely reason for this is use of drenches that are ineffective due to worm resistance, according to Dr Love. 

“Producers should always check the effectiveness of any product they use by conducting a worm egg count 10 -14 days after the drenching,” he said.

“Recurring worm problems can occur when animals are introduced to pastures which have been heavily contaminated with worm larvae by the previous stock, usually young animals with significant worm burdens.”

Dr Love said worm problems in beef cattle mainly occur in animals up to 18 -20 months of age, after which they develop a reasonable immunity to roundworms.   Routine treatment of adults is rarely required, apart from drenching for liver fluke if necessary.

The most important worm affecting young cattle in NSW is the round worm Ostertagia – or small brown stomach worm - which can cause scouring and weight loss.

Young cattle may require up to three drenches between weaning and 20 months of age, depending on the locality. After treating young cattle, they should be moved to pastures not grazed by young cattle for the preceding four months.

Further information is available from the department’s website at www.dpi.nsw.gov.au.