Vets are warning dairy farmers in south-east NSW to be on the lookout for signs of the paralysing disease, botulism.
Local Land Services district veterinarian Helen Schaefer, based in Bega, said there was a lack of awareness about botulism. A south-east NSW farmer lost 10 dairy cows to botulism several months ago in which many of the common signs of the disease were not expressed in the cattle.
“What’s happening in these intensive industries where we are using conserved fodder in the form of silage or large hay bales, you can get things like rodents and snakes incorporated into that feed,” Ms Schaefer said.
“Under the right conditions you then can get bacteria producing those toxins in that feed and that can then be consumed by the dairy cattle.”
The toxin then travels through the blood stream and attacks the nerve endings causing paralysis. With high doses this can lead to sudden deaths but low doses can present as muscle weakness.
“There have been cases where it can have a dramatic impact, there was a case in Ireland a few years ago where a farmer lost 55 per cent of his dairy cattle,” she said.
“What we’ve become more aware of lately is that the signs might be more subtle – where you are not getting the sudden deaths but the cost on production and cattle can be nevertheless very significant.
“Rather than getting the sudden deaths where you walk out the door and you have 50 cows dead.
“In these cases it might be 10, a dozen or 20 cows going down over two to three weeks, they don’t respond to the normal milk fever treatment, the main sign they show is is muscle weakness so they just can’t stand up.
“In this particular case some of them had to be euthanased because they didn’t recover and others spontaneously recovered and got up. For some all they needed was the farmer there to give them a lift on the tail that gave them enough impetus to stand.
“So those signs of spontaneous recovery, not getting up, and no response to metabolic treatments is not typical in anything other than botulism.”
While there is a vaccine available to prevent the disease, take-up is low among dairy farmers.
“We’d recommend the annual vaccine that does provide really good protection,” she said.
“It’s a good insurance policy if you’re using conserved fodder, particularly in the form of a partial or total mixed ration, where you are tending to mix up silage with grain and other products.
“You’re getting a wide dispersal of that toxin, that might have just come from one rat, that got caught in the silage but then gets spread through potentially your whole herd.”
Source : ABC Rural