Undetected drench resistance estimated to cost the NZ sheep sector $48 million a year and it's getting worse 

31 August 2020

Dunedin NZ: Drawing on data collected from sheep farms across New Zealand over the past 15 years, Techion is predicting the incidence of drench resistance to triple combination drenches could rapidly increase to 40% if farm practices do not change.

Techion founder and CEO Greg Mirams said drawing upon DrenchSmart test results collected from 2005 to the end of July 2020, the company has seen the incidence of drench resistance increase substantially. DrenchSmart is a faecal egg count reduction test (FECRT) that reports to farmers which drench actives are working effectively on their farms and which are not.

“In 2005 the resistance to combination drenches was low to non-existent. However, now it is becoming far more common, even to triple combination drenches. Results show double combination drenches are failing on between 20% and 43% of New Zealand farms, while triple combination drenches are currently failing on 15% of properties we have tested.”

“We’re not trying to be alarmist. We’re simply drawing upon a significant body of data collected over a decade and-a-half which proves, without a doubt, drench resistance in New Zealand Aotearoa is increasing rapidly. If farmers continue to use drenches the way they have for the past four decades, drench resistance will continue to develop. The problem is impacting animal welfare and performance, farm productivity and hurting New Zealand meat exports.”

Mr Mirams quoted Beef & Lamb NZ statistics which show New Zealand farmers sent 18,000,000 lambs to slaughter in the 2019-2020 financial year. Studies have shown that undetected drench resistance can reduce carcase value by 14%. This translates to undetected drench resistance costing the sheep sector in the region of $48 million per year in 2020. At an individual farm level, for a property producing 4000 lambs per year, undetected drench resistance could cut income by $71,169 per year. Undetected drench resistance is a significant issue as few farmers have tested drenches on their properties.

If this trend continues and Techion’s prediction of 40% of farms being impacted by combination failure in ten years is correct, that would equate to a $128 million productivity loss per annum.

Veterinary parasitologist from Dawbuts Australia, who presented on worm diagnostics at the New Zealand Society for Parasitology annual conference last year, Dr Matt Playford said, “Simple tests can detect drench resistance and estimate exactly how bad it is. Once the test is completed, farmers can choose the appropriate drench and immediately see the benefits in growth rates, as well as in wool production and lactation. Choosing the right drench program also helps prevent pasture larval contamination and ensures that drenches last longer.”

“It’s critical farmers test the efficacy of the drenches they use and utilise alternative measures to control parasites and protect the drenches which are still working effectively“, Mr Mirams says.

He cites international scientific research about slowing drench resistance in a paper published by Dr Ray Kaplan earlier this year, which recommends proven practices farmers can use to slow drench resistance.

Dr Kaplan recommends farmers conduct drench resistance testing every 2-3 years so that they know which drenches work best. New animals should be quarantined and treated with the most effective drench available. Farmers should undertake a faecal egg count test (FEC) before and after drenching and only let animals join the farm if the FEC is negative after 14 days.

The final word rests with a Central Otago farmer who – after looking for answers for 18 months – has recently confirmed the property is resistant to all drenches, except one. “I’m too scared to try and work out the cost. The wastage, the death rate, the loss of productivity and weight gain failure.” The farming veteran of 20 years explained the toll prolonged stock deaths took. ‘its physically and mentally draining losing good stock. It’s hard to drive around the farm when you know what’s waiting for you. I urge people to get in and get a test if they have any doubt. Leaving it isn’t pretty.”