Insecure property boundaries, mixing cattle on grazing blocks, not recording on and off farm animal movements, sharing milk and colostrum for calves between properties, single NAIT numbers for multiple properties and not recording cattle movements between those properties, shared milking platforms, and inconsistent information from farmers, continue to be risky farming practices that need to change, M bovis programme director Stuart Anderson said.
The M bovis programme has expanded the National Beed Cattle Surveillance project to target surveillance of 2019-born heifers in Canterbury, Otago and Southland.
Anderson says in spring 2020 the programme saw the effect of untraceable young stock from 2018, in particular dairy heifers entering the milking platform for the first time.
“We now have 2019-born heifers due to calve and come into lactation for the first time this winter.
“Where we can, intercepting infected dairy heifers before they mix on a milking platform and contribute calves to the population, will reduce the risk of possible spread within and between more farms.
“To do this, we have expanded our beef cattle surveillance with a rapid seasonal push to test a larger number of dairy heifer groups in areas where we have seen a higher prevalence of M bovis.”
Meanwhile the first of the Mid Canterbury cluster of properties confirmed infected in spring 2020 have been cleaned, cleared and able to get back to farming.
It is expected the seven remaining properties will be fully depopulated with cleaning and disinfection completed by the end of May, and Restricted Place notices revoked in June.
Before eradication can be achieved, the Five Star Beef (FSB) feedlot in Mid Canterbury must be depopulated and cleared.
MPI chief science adviser John Roche is working with international animal health and feedlot farming experts to determine the appropriate approach.
The timing of depopulation has not been decided yet, but FSB will be one of the last, Anderson said.
Beef and Lamb NZ chief executive Sam McIvor says FSB has been useful to the pogramme to test incoming animals from source properties.
“This has saved a lot of farmers’ time and all of these source stock have tested negative, building our confidence that M bovis is not widespread in the beef industry,” McIvor said.
FSB is visited regularly to ensure it complies with the Restricted Place notice and biosecurity controls, and contrary to some belief, is not proving to be the source of the Canterbury cluster.
Anderson says FSB has proved highly compliant with the most recent inspection confirming no evidence of boundary weaknesses between the feedlot and neighbouring farms.
Current conditions include no live cattle movements off the feedlot other than to processing and no over the fence contact between cattle within and outside the boundaries of the Restricted Place.
Additional conditions for lower risk pathways off the site are in place.
These include animal products, personnel, clothing and protective gear, equipment, effluent and vehicles.
As an extra precaution, neighbouring farms are being tested at six-month intervals.
“This plan will be in place until depopulation when a new plan focused on avoiding reintroduction of infection will be needed,” Anderson said.
Epidemiological investigation is ongoing to determine the pathways of transmission within the Canterbury cluster.
Investigations continue to confirm movements of infected animals are the more probable cause, than FSB, of the Canterbury cluster.
McIvor says poor NAIT records have cost the eradication programme and farmers, significantly increasing the time and resources required to trace and eliminate the disease from infected stock.
“Failure to record animal movements in NAIT means that a larger number of farms need to be placed under movement controls than would otherwise be necessary.
“This means that one farmer not doing their NAIT properly can lead directly to other farmers’ businesses being impacted.
“No farmer I know would want to be responsible for this,” McIvor said.
Graziers also must recognise that cattle from different clients must be kept separate on the grazing property and farmers are encouraged to require this in the contract.
“This is necessary to prevent infection spreading between stock and then returning to the home blocks in spring.
“This is known to have occurred in Canterbury,” McIvor said.
