Article 2 in the Future Herd Strategy series

Exporters of pedigree cattle could be missing out on lucrative markets as more EU countries – particularly new member states – show an interest in eradicating IBR.  British pedigree and commercial producers increasingly vaccinate to control other endemic diseases and it is important not to forget about IBR.

Although it is known to be widespread throughout beef and dairy herds, the national incidence level remains unclear, says Intervet’s large animal veterinary adviser Ruth Vernon. “There haven’t been any in-depth surveys, but the disease is growing in profile. Recent results from our DairyCheck diagnostic service show that 34% of samples had current active IBR infection and a further 36% had been exposed to infection. Once infected, an animal stays infected for the rest of its life, shedding virus intermittently,” she says.

Depending on the farm circumstances and the severity of the disease, it may not always be considered to be economic to vaccinate.  Whereas there may be a definite cost benefit for pedigree exporters using a marker vaccine, for the vast majority of commercial farmers, it’s about controlling IBR cost effectively, says Ms Vernon. She points out that vaccination is becoming particularly relevant as increasing numbers of dairy herds choose to rear replacements off farm.  Bovilis® IBR maybe the vaccine of choice for many vets and farmers, because it  offers two routes of administration – intranasal or intramuscular.  Ms Vernon believes that it is this added flexibility makes it such a popular choice.

“Anything newly introduced into the herd could be naïve and infected very quickly once it enters the herd. When heifers return to calve, therefore, they are under stress and exposed to circulating virus. Bullied by older cows, they have to deal with new feed and housing and it’s just another thing to cope with,” she explains.

“Sometimes they show obvious signs – runny nose and eyes, and a cough – but symptoms can also be quite subtle and just contribute to overall poor health. Ultimately, IBR affects performance. A naïve animal will experience a sudden drop in milk yield and dry matter intake, even if just for a few days when she seroconverts. When this happens at peak production, there is a knock-on effect to fertility and production.”

Although he believes an IBR eradication programme would be ideal, Scottish vet John Baillie says herd health planning is beginning to make a difference to farmers’ awareness of the risks and consequences of diseases like Johnes and IBR. And it has recently been given a boost by funding through the Land Management Scheme. Now in its second year, the scheme awards £220/year for five years to producers who prepare and act on a health plan drawn up with their vet. An additional £320/year is paid to those producers supplying performance figures to a central database. This will shortly be launched as a benchmarking programme.

“Producers can then compare themselves with the average farm, or others like themselves, in the parish, county or the whole of Scotland,” says Mr Baillie, a partner with Clyde Vets in Lanarkshire. He explains that although farms already had some sort of health plan for farm assurance, this scheme aims to ensure it is acted on and doesn’t just sit in the shelf, gathering dust. “A farm in the scheme must now have a first and second line treatment protocol for all diseases on that farm. In addition, it needs a prevention programme to minimise or prevent disease.”

With 40% of the practice’s full-time farmer clients already signed up, Mr Baillie is pleased with the chance to build better relationships. “The biggest benefit for us has been sitting down with farmers to review herd health and find out their livestock health status. It has allowed farmers time to discuss their concerns about the consequences of diseases like IBR and in conjunction with the vet plan a strategy of vaccination and eventual disease elimination.  

Highlighting common endemic diseases such as IBR persuaded some farmers to sign up for control programmes. But all have discovered the consequences of such diseases. “It’s certainly made farmers more aware of what diseases they could be buying in, the consequences, and how to implement a proper and economic control plan. Some producers still view endemic diseases as a fact of life, but they are now more aware it is costing them money and they can do something about it.

“As a practice, we are fairly active in encouraging vaccination. The trouble with IBR vaccination in dairy herds is that the vaccine successfully controls the abortions or respiratory disease. The result is farmers believe they can stop vaccinating after only one or two years. With biosecurity measures, some could, but others could not, so we need an exit strategy.”

Putting money into schemes to make herds free of endemic diseases such as IBR would benefit Scottish herds, he adds. A control strategy would need to divide herds into those that are IBR-free and keep them that way, and those that have it but need a marker vaccine to control it and eventually be free. “Vaccination only stops disease from spreading though, and a scheme would have to be implemented with the support of a vet to ensure correct management and biosecurity measures were in place,” he adds.