DUE to the long incubation of Bovine Johne's Disease, researching the disease and potential vaccines is difficult and drawn out.
Zoetis technical services vet Sally Oswin discussed a vaccine trial during an educational meeting at Rockhampton for cattle producers earlier this month. The trial is in two endemically infected dairy herds in Victoria, in which half the cattle received the vaccine and half did not - the most difficult test for a vaccine, she said.
She said the results were still applicable to beef herds but BJD was more common in dairy cattle due to the wet and muddy environment they are raised in and their intensive management, particularly in herds of older average age.
They don't want to test - they don't want to know and the control programs and all these assurance programs have really only recruited small numbers of properties.
She said because it could take years for cases to become clinical, beef producers may never know their cattle have BJD, because often they don't keep their cattle for that long.
The trial has shown some positive results.
The data is demonstrating the vaccine appears to have an impact on the number of animals found to be shedding the organism post-vaccination in endemic herds, particularly younger cattle.
"These animals are being run with controls that are shedding. If you vaccinate your whole herd, I'm sure the results would look significantly better again," she said.
"The problem is you can't vaccinate a calf and then sell it one day and say 'it's clean, it's had a vaccine'. You can say it's very likely.
"One of the biggest problems with this disease is there is no affordable, reliable test."
The vaccine is available on permit in southern states but not in Queensland due to its protected status. There are some complications with the vaccine, though.
"If you do a TB test on an animal that has been vaccinated, it may come up TB positive," she said.
"You can do a comparative test where you give Bovine TB and Avian TB on the same side of the neck and you will determine it is not TB.
"I think there's only one export market now that requires a TB test but this can be managed as long as vaccinates are permanently identified."
She said the vaccine would cost about $20 a head.
In the southern states, the stigma was a bigger problem than the disease, Ms Oswin said.
"In Victoria, most farmers are not testing," she said. "They don't want to test - they don't want to know and the control programs and all these assurance programs have really only recruited small numbers of properties. So the vast majority of farms are just living with it and dealing with it in their own way.
"There's probably some productivity impact on their herds but I think the cost involved with being in the test and control programs - especially with the dairy industry the way it is - is just not an option.
"They've got bigger problems," Ms Oswin said.
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