Change to M.bovis sample protocols
THE Mycoplasma bovis (M.bovis) eradication programme has made changes to on-farm sampling protocols, and how it interprets results from the testing of blood samples.
The changes will reduce the amount of time that many farms spend under ‘active surveillance’ and ‘notice of directions’ in the future.
“This is a positive step forward in reducing the impact on farmers from sampling and testing for M.bovis,” said Dr John Roche, the Ministry for Primary Industries’ chief science advisor.
“Our scientists have analysed the results from hundreds of thousands of samples. From that, they have refined our sampling criteria to effectively halve the number of rounds of sampling and testing required for many farms, while ensuring we still correctly identify infected management groups.”
Dr Roche said the changes mean that, where possible, blood samples will be collected from more cattle each time a property gets visited.
“But for many farmers only one round of sampling and testing will be required if the management-level results from the first round are negative.?“It is important to keep in mind that more testing might be required in the future if other risk events are found,” he said.
Most farms under active surveillance will only have to muster animals for one round of sampling, which will reduce the impact of on-farming testing on their operations.
Beef and Lamb New Zealand technical policy manager Chris Houston said many beef farmers will have to wait half as long to have an all clear, and get back to their business as usual.
“It could mean a reduction of up to five weeks of waiting for farmers to get a result, which is a great step forward.”
The eradication programme will also change the way it interprets results for blood samples, based on expert analysis of the hundreds of thousands of samples tested to-date.
“The threshold for designating an individual animal as a ‘reactor’ will increase to a seropositivity ratio threshold of 90 percent or greater,” Dr Roche said.
Correspondingly, the percentage of ‘reactors’ per management group required for a round to be determined positive will decrease to a cut-off point of 3 percent.
“There will no longer be suspicious rounds, only positive or negative.”
The latest MPI situation report indicates no ‘active’ properties with M.bovis identified in Tairawhiti.
Three properties that had been ‘active’ earlier this year have now been cleared.