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Hunter farmers to benefit from dairy heifer drench resistance trial

Do you know if the de-worming drenches used on your dairy heifers are effective?  Are you drenching too frequently and wasting money or not frequently enough and suffering growth losses? Hunter Local Land Services is looking for local dairy farmers interested in participating in a dairy heifer drench resistance trial.

The study, being undertaken by Hunter Local Land Services, in partnership with Hunter Dairy Development Group and the Mid Coast Dairy Advancement Group, aims to identify if drench resistance is occurring on Hunter farms.

According to Hunter Local Land Services District Veterinarian Dr Lyndell Stone, a number of studies conducted elsewhere have found resistance to cattle de-wormers is an increasing problem.

“We only have a limited range of active anthelmintic groups and once resistance develops on a farm it takes a concerted effort to remove the resistant worms.” Dr Stone said.

“This trial will save Hunter farmers time and money, by identifying the effectiveness of their current drenching program and pinpointing which worm species are present in our region.”

Several mid coast farms have already participated in the trial, with important results.  Some producers have been able to reduce the frequency of drenching, whilst others have found that their preferred drench is no longer effective, due to drench resistance, For others it has confirmed worm control practices are performing well.

Drench resistance, resulting in daily growth losses, often goes unnoticed.  Resistance may only become apparent when drench efficacy is tested or its reaches a point where burdens cause obvious losses such as scours, ill thrift, anemia or stock deaths.

District Veterinarian Lyndell Stone said the trial is already helping local farmers adjust their programs.

“Rotating deworms or using broad spectrum combination products as well as integrated parasite control is the best way to slow resistance,” Ms Stone said.

“However, the most important principal is to know you are using drenches that are still effective on your farm.”

Dairy farms with 60 heifers or steers, preferably under the age of 12-15 months, are invited to enroll in the trial.  Each farm in the trial will receive free worm egg counting for the group, each animal will be drenched and each class of drench currently available in Australia, will be tested on the group.  Producers will receive a report indicating current worm burdens and effectiveness of each drench class on your farm. Producers will need to yard test animals twice, 14 days apart.

To join the trial or for further information please contact Lyndell Stone on 0429 532 855 or  At the minimum, we can call out and conduct a free worm egg count on a sample of heifers to assess current worm burdens.


Media contact: Penny Evans, Hunter Local Land Services, 0417413026