Farm study raises drenching alarm

TIMARU - A scientific trial shows parasites on New Zealand cattle are more drench resistant than are such pests in any other country in the world.

Lincoln University lecturer Dr Alex Familton, who worked on the year-long trial involving 7400 cattle under two years of age, said the results were frightening.

The "snapshot" from his study suggested eight of the twelve farms in the study still had significant parasite problems even after cattle had been drenched. The problem had been most noticeable among bull beef cattle, but was also significant on dairy farms.

The Cattletech Project was supported by a Government science grant under the Technology for Business Growth scheme.

The results were presented to South Canterbury farmers by Dr Familton and Greg Mirams, the managing director of a Dunedin company marketing faecal testing systems.

The system took 18 months of research and testing. Trials had shown that, like sheep farmers, cattle farmers could count the parasite eggs in a sample of faeces and then calculate whether drenching was warranted, rather than just applying it at regular intervals.

Dr Familton said drenching too often helped to make parasite populations chemical resistant.

There were only three chemical "families" of drenches, and resistance to even one could reduce a farmer's options for worming. Real dangers of multi-resistant parasites occurred if farmers started mixing the families.

Regular testing also highlighted parasite problems outside expected risk periods.

More sheep flocks have also shown resistance to existing chemical drenches, and there were no new chemicals available to kill parasitic worms. In some parts of the world, the parasitic resistance to drench has made sheep and goat farming unsustainable.

In New Zealand, increasing attention has been paid to developing pastures which confer a natural protection against parasites, breeding sheep with a natural immunity to parasite infection, and developing techniques to use drenches only when necessary, to slow down the incidence of resistance.

Mr Mirams said his screening system had revolutionised sheep drenching practices and he now exports it to Australia, Britain and the US.

Experts were only beginning to realise the extent of drench failure in New Zealand cattle, he said.

Dr Familton said an analysis of the eggs showed that cooperia was the main problem and it appeared to be a significant problem for drenches to combat.

"Cattle with a cooperia problem are really sick. I haven't seen them die but some have been pretty close."

The Green Party's agriculture spokesman, Ian Ewen-Street, said he was concerned but not surprised by the drench resistance in cattle.

"Much of New Zealand's nonorganic agriculture is completely dependent on chemicals," he said.

"Studies like this perfectly illustrate the dangers of chemical dependence."

He was concerned that years of breeding animals to be productive with the support of dips, drenches, sprays and antibiotics had, in effect, developed chemical dependent livestock.

This was one reason the Green Party wanted New Zealand agriculture switched to organic production systems in the next 20 years.

- NZPA