TWO diseases of major importance to the beef industry – bovine johnes disease and pestivirus – were in the spotlight at three SA Beef forums held across the state last week.
Biosecurity SA senior veterinary officer Jeremy Rogers said there had been misinformation about the transition from the government regulation of BJD to producers managing their own risk.
He stressed the new Johnes Disease Beef Assurance Score – which provides a J-BAS score from 0 to 8 – was voluntary.
“We think johnes disease is still important and would recommend that you think about it and do something about it,” he said.
“But you don’t have to have a biosecurity plan, you don’t have to have a J-BAS score, you don’t have to fill in the johnes section of the Cattle Health Declaration, but if you do, it is a legal document.”
BJD attacks the gut and slowly leads to wasting with the average infection age 10-12 years.
Dr Rogers said it was up to individual producers to decide what level of assurance they wanted for their herds when selling animals or buying replacements.
Herds with no history of johnes disease in the past five years were a J-BAS score 6, but herds wanting to be a J-BAS 7 and 8 required written biosecurity plans signed off by a veterinarian.
SA herds wanting to trade with WA need a J-BAS 8 status.
Dr Rogers said only 25 per cent of SA dairy herds were infected and two beef herds. These were no longer under quarantine and these animals could be traded freely in the market.
”You could be buying from a herd that has the disease and unless you ask, they are not obliged to tell you so you will be bidding on these animals and they will look just like a J-BAS 6 (animal),” he said.
Dr Rogers said SA’s low prevalence was worth keeping, with Vic research showing infected dairy cows were costing about $1200 an animal in reduced calf and milk sales.
For beef herds, the productivity losses were far lower than dairy but Dr Rogers said the advantage of taking steps to remain disease-free was for better market access, especially in export markets such as Japan.
“Some producers were prevented from shipping to Japan recently due to BJD restrictions,” he said.
Consumer perception was also a major concern, with some research linking BJD to human health diseases.
“It is one of those diseases, if you don’t manage it or do anything about it, it will creep up to a higher level,” he said.
“Australia is in a favourable position compared to the United States and Europe which have much bigger issues and I think we should stay that way.”
BJD remains a notifiable disease and Dr Rogers encouraged any producers with suspect animals to contact their local PIRSA veterinary officer.
“It is not as simple as shoot it and put it out the back,” he said. “You might have one or two animals that might be showing signs – they are the top of the dung heap and an indicator you have a widespread problem.”
Dr Rogers said PIRSA’s role was to give quality advice on how to manage disease.
He said a vaccine was available, offering lifetime protection, but it was expensive at $35 to $40 a dose.
Permission for use of Silirum, manufactured by Zoetis, required approval from the chief veterinary officer and to-date only one SA herd was using it.
Zoetis sales manager Gary Glasson spoke about pestivirus, which can cause abortions, ill thrift, diarrhea and respiratory disease.
A recent Meat & Livestock Australia survey found it was the second most costly animal health condition to Australian beef producers, behind cattle ticks, at $114 million a year.
Production losses as high as 25pc are seen in recently infected properties.
Up to 90pc of the spread of the disease is through persistently-infected animals, which shed pestivirus for life.
Mr Glasson said producers had several control options – vaccination, partial vaccination of heifers, deliberate exposure to persistently-infected animals, test and eradicate persistently-infected animals or rely on biosecurity to prevent the introduction.
He said vaccination was a great form of insurance.
“If you are not going to do the whole herd, at least do the heifers to protect your best genetics and your bulls,” he said.
Mr Glasson was also a big believer in blood testing 5-10pc of a herd or individual mobs to determine previous herd exposure.
“It might be a cost, but at least if you know it will help determine what program to put in place,” he said.
