BVD: ‘more proactive steps’ needed - Veterinary Practice
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BVD: ‘more proactive steps’ needed

Veterinary Practice reports on the findings of the Farming Against BVD survey which revealed farmer attitudes to the disease.

IT is unsurprising that many farmers do not show a greater understanding of BVD beyond the biological side-effects present in infected cattle, Professor Joe Brownlie told a recent meeting about the disease.

This followed the announcement of the results of the Farming Against BVD survey, in which 301 dairy and beef farmers in England and Wales, representing more than 70,000 cattle, answered questions about bovine viral diarrhoea.

The survey found that nearly half of farmers talked to vets, their main source of information about BVD, only once or not at all each year, “About 50% of farmers surveyed were unsure as to what types of tests need to be carried out to detect the infection in their livestock and 32% of respondents were unaware that correct vaccination of livestock against BVD can protect both the cow and unborn calf,” Prof. Brownlie said.

Moreover, whilst BVD is still regarded by farmers as one of the top bovine diseases, other health issues such as mastitis and tuberculosis are given much greater attention. This lack of focus on BVD is exacerbated by the lack of sound information of the financial implications of the infection on their herd.

“The side-effects appear to be overlooked in financial terms,” Prof. Brownlie continued, “but the infection can severely hinder a herd’s financial productivity due to poor health, reduced milk yield and loss of reproductive efficiency.”

Farming Against BVD (FAB) is an initiative by Novartis Animal Health in conjunction with the RVC and McMurtry & Harding Veterinary Practice in Derbyshire.

The project, aimed at increasing farmer awareness and understanding of the virus, has been driven by a panel of industry experts, including Prof. Brownlie of the RVC, who chairs the BVD scientific and technical working group; Caroline Dawson, professional services veterinary surgeon at Novartis; Tony Brooks, herd manager at Brighthams Farm; Dr Peter Nettleton, Fellow of the Moredun Research Institute; and James Russell of McMurtry & Harding.

Whilst effective vaccination against BVD has been available for the last two decades, the disease continues to cause significant problems in the cattle industry, with infected cattle suffering from abortion, infertility and suppressed immune systems, leading to poor productivity.

Follow-on project

“Perhaps by aiding understanding of the financial cost of the virus, we can encourage farmers to take more proactive steps to combat BVD,” said Caroline Dawson, who announced that the FAB panel has initiated a follow-on project to carry out detailed research with regards to the financial impact of BVD on farms and is due to report findings in the new year.

The findings of the latest survey, which revealed dairy and beef farmers’ current practices, attitudes and understanding of BVD, were presented by the expert panel on 18th September.

The findings showed an inconsistent approach to the disease and demonstrated the need for more targeted advice to help tackle it.

“BVD is a serious, industry-wide problem and one that farmers are clearly aware of, with over 70% of respondents having a herd health plan that incorporated BVD,” said James Russell. “However, the survey reinforced that much work needs to be done in providing practical advice about how farmers tackle the virus in their herds.

“What is deeply concerning is that 49% of farmers questioned had not tested their herd for BVD in the last 12 months and of those that did, 83% did not go on to test their young stock. “So whilst farmers may be aware of BVD, there appears, on this evidence, to be a disconnect between awareness and practical activity in the detection and then eradication of infection from their herd.”

Failure to identify PI livestock

One of the most significant findings of the report was the attitude of farmers towards testing and subsequent failure to identify persistently infected (PI) livestock within their herd.

Any calf born from a BVD persistently-infected cow will be born persistently infected with the virus and cannot be cured. As a result, future vaccination of this animal against the virus is rendered ineffective and the affected animal will be a source of the virus, spreading infection within the herd.

With young cattle being the source of PIs and reservoirs of infection within a herd, failure to test, identify and then deal with PI livestock represents the most significant problem facing the industry when trying to eradicate BVD.

Prof. Brownlie voiced his worry that 39% of farmers who found BVD present in their herd did not then go on to test for PIs.

“Of the 61% of farmers that did do follow-up tests for PIs once BVD had been detected in their herd, one third found one or more PIs within the stock holding.

“In addition, one third of farmers who identified having active BVD infection in their herd then failed to go on and carry out individual animal testing; of those that did, nearly half discovered one or more individual PIs within their herd.

“It just shows that the disease can be hidden,” he said, “and farmers could be in the dangerous position of potentially missing PI animals that are in their herd; PIs that can continue to spread the BVD virus amongst other cattle and pass on their PI status to any calves they produce. It is hugely important to be thorough and consistent in testing as part of an agreed herd health plan.”

The survey also indicated that action needs to be taken to educate farmers about what to do once BVD and PIs are discovered amongst a herd.

“There is much evidence from this survey to encourage the industry in how it is tackling this disease,” said Prof. Brownlie; “however, there is still a great need for clear direction. “The survey indicated that 20% of farmers wrongly believe that PI animals will eventually become non-infective and that 25% believe that calves born of PI cows will not always have PI calves themselves.

“All of these perceptions are incorrect and can lead to reservoirs of the disease being allowed to remain not only within individual herds, but geographical regions as well; seriously hindering the eradication of the virus in England and Wales.”

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