Aiming to break the cycle

By Country News on January 20, 2016

A young scientist working in a northern Melbourne laboratory might be making a major difference to Macalister Irrigation District dairy farmers.

Jane Kelley, who grew up on a beef and fodder production farm at Cowwarr, is conducting research at Latrobe University Bundoora into liver fluke, which would appear to be a growing problem for the district’s farmers.

Liver fluke is caused by a parasitic trematode which enters a cow’s digestive system when they eat snails attached to grass.

Once in the animal’s gut it moves to the liver, causing damage to the organ and spreading eggs back through the digestive system, allowing its breeding cycle to continue.

MID cattle are particularly vulnerable to the parasites because snails thrive in the moist environment caused by irrigation on pastures.

The problem also occurs in the Upper Murray and, to a lesser extent, in the Goulburn Valley dairying areas.

While liver fluke issues have been controlled over recent decades by the use of triclabendazole-based treatments, Ms Kelley’s research has reported an alarming increase in resistance to the treatment, with a resulting spike in liver fluke cases per herd.

“In MID last year we tested 400 cows across 20 farms and found that 73 per cent of those were infected, which is really high,” she said.

“When we get prevalence above 25 per cent, that is our cut-off for production loss. So when you get an overall regional prevalence of 75 per cent it is a real concern to me.”

Some farms being studied in the PhD student’s research have seen 100 per cent of animals suffering liver fluke infections, which will inevitably result in serious production loss for the dairy farmer.

While similar conditions exist in the Goulburn Valley, prevalence of the condition is much lower than in the MID.

Ms Kelley believes that finding the reason for the different rates of liver fluke occurrence could be a key in helping MID farmers control the issue in their cattle.

“We believe it may have something to do with salinity in the Goulburn Valley which is killing off the intermediate host (the snail),” she said.

“We will be doing more work on the Goulburn Valley to see if there’s a management strategy there that we can implement in the MID to maybe reduce that prevalence.”

“In the Upper Murray, 120 cows were tested and 66 per cent of those were infected, but we will be expanding that out further and testing more animals on more farms.”

The PhD research, which is entitled Epidemiology and management of liver fluke in irrigated dairy regions of Victoria, hopes to build on the liver fluke knowledge base, which has remained fairly static for more than 30 years.

 “The last big survey in Victoria looking at the prevalence of liver fluke was in 1980 and nothing has been done since,” she said.

The release of Fasinex onto the market helped control the parasite, but if resistance indications are true, a new control method may have to be developed.

Jane said the potential flare-up of liver fluke was no-one’s fault, but work needed to be done to stop it affecting production levels on farms.

“I don’t blame the farmers and I don’t blame the veterinarians, they’ve done a fantastic job and there hasn’t been an issue so they assumed it was under control,” she said.

“We now have the situation where on one of those farms where there is drug resistance we’ve had clinical deaths, which is very uncommon in cattle. They died from having huge numbers of liver fluke in their liver and egg counts that were extreme.”

The 26-year-old has just received a Rural Finance scholarship to help with her research, which has been funded in the past by Dairy Australia.

With the disease costing, in rough estimates, around $28000 per infected farm each year, investment in the research would seem to be money well spent.

Ms Kelley is also working with DEDJTR and vets including Maffra’s Jakob Malmo.

By Country News on January 20, 2016

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