SOUTHERN Queensland beef producers will have an opportunity to learn more about bovine viral diarrhoea virus (BVDV) when a leading specialist on the virus visits Roma on December 10.
Originally from the United States and now working with Swans Veterinary Services at Esperance, WA, Dr Enoch Bergman (pictured) came across his first case of BVDV in Australia nine years ago.
He was shocked when told that Australia had no vaccines commercially available to manage the virus at that time.
Having worked closely with livestock producers managing the virus in the US, where vaccines had been widely available for many years, Dr Bergman began investigating the tools necessary to manage BVDV in Australia.
His work had him conduct several surveys and trials on the virus, and led him on a crusade to see Australian beef herds become free of BVDV.
"Most of Europe is in the process of eradicating the virus, proving that it is achievable," he said.
"My goal is to work with individual Australian producers and their veterinarians to manage the virus in their herds and to even eradicate it from their herds altogether."
In 2003, Pfizer Animal Health released a vaccine for BVDV in Australia, known commercially as Pestigard.
Two years later, Dr Bergman conducted a trial to determine the level of benefit producers could expect from using the vaccine in their herds.
"We vaccinated 1600 animals across eight Esperance properties," he said.
"The vaccines were administered randomly some heifers were vaccinated and some were not on each property.
"Then we turned the bulls out having recorded those that had been vaccinated.
"When we pregnancy tested, we determined pregnancy rates among the vaccinated heifers versus those not vaccinated.
"Remarkably, we got a 16pc better conception rate within the vaccinated animals.
"I am often reluctant to bandy that figure around because I don't want people to assume that they will get a 16pc improvement in their calving rate just by vaccinating for BVDV, but it does highlight the extent of the problem and the efficacy of the vaccine.
"Vaccinating costs around $5 a shot, and animals need two shots in the first year and an annual booster from then on."
Dr Bergman said vaccination was not the only way to manage BVDV.
"Vaccination is an important tool; however, it is only part of a systematic BVDV control program," he said.
"Vaccinating immune animals is a waste of resources and vaccinating carrier animals does not change their status.
"Lastly, like all vaccines, Pestigard will not prevent all of the losses or prevent all of the PIs (persistently infected) from being born.
"Vaccinating animals without immunity prior to their joining the breeding herd is a good investment."
Dr Bergman has also established Australia's first commercial laboratory for the diagnosis of animals PI from ear notch tissue.
Prior to his pioneering the service in Australia, producers had to use blood samples both costly to collect and test.
"My goal was to simplify the process of identifying PI animals," he said.
"As my advice has matured with experience, we have added other testing options to address individual producer needs."
Rachel Wilson from the Roma Vet Clinic said BVDV was still a big issue across Queensland.
"BVDV is endemic in nearly every beef herd, and it's certainly worth testing your herd to check their exposure," she said.
"About 60pc of our clients get us to do regular blood work and monitor the virus in their herd.
"It's a complicated virus, and management programs will vary from property to property, which is why it would be very beneficial for producers to come along and hear from Enoch Bergman, who is a leading specialist on this virus."
Mitchell beef producers Don and Kim Noon, Cedarvale, implemented a pestivirus management program in their herd of 800 cows six years ago.
Mr Noon said it was an expensive but worthwhile program.
"We always preg test and found that we were getting some leakage between what was confirmed pregnant and our actual calving, so we had a sample of the herd tested and decided to go on a pesti program six years ago," he said.
"Our exposure was pretty high about 70-80pc but we felt that wasn't high enough to protect us.
"The vaccine is dear enough, but given the improvement we have seen in our calving rate, I think it is well worthwhile.
"The negative is that the herd has no natural immunity, and if for some reason you don't vaccinate one year, then you have massive exposure, but we took that on board and vaccinate on an annual basis."
l Dr Bergman will speak at the Roma Bowls Club on December 10 from 6.45pm to 8.45pm. He will explain how BVDV is spread and maintained on properties, outline some of the costs of the disease and discuss control options.
- For more information contact the Roma Vet Clinic on (07) 4622 1015.
What is BVDV?
BVDV, also referred to as bovine pestivirus or mucosal disease virus, is a virus that is now recognised as an insidious cause of significant losses in beef and dairy herds in Australia. BVDV affects all types of cattle.
In herds recently infected with BVDV, production losses of 25 to 40 percent have been recorded due to reduced reproductive performance, death losses and ill thrift.
If BVDV stays in the herd, annual production losses of 5 to 10pc commonly occur.
BVDV has been demonstrated from international trial work from all corners of the globe to cost beef and dairy producers from $15 to $100 per breeder per year in production losses, predominantly due to its reproductive impact and immunosuppressive capability.
Persistently infected animals (PI's) are the primary vector for BVDV transmission.
Their ability to continually shed the virus at massive levels for their entire lives has proven to be an exceptionally successful course for viral continuance, proven by the fact that more than 70pc of Australian farms are actively infected with BVDV.
Management programs for the virus vary from property to property, but some tools are available to help manage BVDV. These include:
- Antigen testing (PI testing) - Tests designed to diagnose animals persistently infected with BVDV.
- Antibody testing - Tests designed to document evidence of immunity to BVDV, either from past exposure to the virus, from vaccination or consumption of colostrum.
- Vaccination - Currently there is only one commercially available vaccine for BVDV in Australia. It requires two preliminary doses from four weeks to six months apart, followed by annual boosters.