Drench resistance could be costing the merino wool industry more than $1 million a year in lost production, a three-year research project has found.
Data collected from the S3 sustainable parasite management project, extrapolated from the $120-million merino wool clip, reveals an annual cost from the loss of wool production of over $1 million.
Further research was still to be done on the cost to the mid-micron wool industry, but Fecpak International business development manager Sarah Hill said there were management steps farmers could take to reduce the impact.
"If we apply what we have learnt from the project and applied it across the merino industry, we could be looking at just over $1 million in annual wool production loss.''
That was based on the industry right now, and if drench resistance grew, so would the cost to the industry.
Merinos were susceptible to internal parasites due to their habit of eating in the same places and camping together as a mob.
For three years, the S3 project monitored 37 mid-micron Corriedale and merino ram breeding properties, analysing parasite species, the resistance status of animals and properties, quarantine protocols, dag score, faecal egg count, cost of production and cost to the industry.
Mrs Hill said there were basic steps farmers could take to reduce the impact of drench-resistant internal parasites, but the key was realising that every farm was different, as was every flock of sheep.
Two neighbouring properties in the trial had completely different parasite species and Mrs Hill said that reflected management, climate and water availability.
The trial has also revealed parasite species were no longer influenced by seasonal trends.
"Seasons do not necessarily dictate the type of parasites present on a property,'' she said.
It was discovered that 42% of farmers in the trial were using drenches that were ineffective, underlining the necessity for farmers to determine what parasites were present in their flocks.
On average, mid-micron growers were spending $1.19 a stock unit on parasite control and merino farmers $1.02, so it was an expensive mistake if the drench was ineffective, she said.
Also, dag score was not accurate in determining parasite infestation.
"In the past, it was believed dag score indicated parasite infestation, but that isn't the case.
The data shows there is no relationship,'' she said.
The dags could relate to diet change or drench making the sheep dehydrated.
Mrs Hill said some highly productive animals in the trial were also found to be carrying high numbers of parasites.
To reduce flock infestation, selection has to be based on productive traits and faecal egg counts.
Culling the bottom 10% to 20% of animals on that criteria would remove half the flock's contamination, she said.
"Don't look at faecal egg count alone. You also have to look at production traits.''
The other tool to come out of the trial was establishing a quarantine paddock so stock leaving and arriving at a property can be cleaned of parasites, stopping their spread between farms.