NML Seminar Reviews BVD Progress
A seminar, organised by milk testing and disease monitoring company NML, brought industry specialists together last week to discuss the progress being made in BVD control here in the UK. Held in Larkhall, Lanarkshire, it was appropriate that Gordon Struth, Animal Health and Welfare Division, Scottish Government, brought the audience of vets and cattle industry stakeholders up to date with the progress being made in Scotland.
Financial incentives offered to Scottish livestock producers have resulted in 4,000 herds screened for BVD in the six months from September 2010 with follow up tests for those with positive results. This has cost the Scottish Government £180,000.
"But the initiative has put vets on more than 4,000 farms to talk about BVD. It has produced excellent data on disease prevalence," said Gordon Struth. "It gave us a sound basis to launch mandatory annual screening."
Work carried out by the Scottish Agricultural College, supported by the Moredun Research Institute, illustrated the viability of an eradication programme. "Industry then came up with a plan that the Scottish Government has taken forward and it has proved popular with a wide range of stakeholders in the industry."
From December 2011 all Scottish cattle herds will be required to have an annual screening test with results from an approved laboratory passed on to the Government. "It is proposed that the sale of all known persistently infected (PI) animals be banned from December 2012," added Mr Struth. About 40% of Scottish herds are affected by BVD.
Seminar speaker Richard Booth from the Royal Veterinary College discussed a pilot BVDV eradication programme for farms in south-west England that started in 2006. "We only have preliminary results but trends are emerging that indicate that the 59% of study farms that were infected at the start of the project were not performing as well those that were BVD free," said Dr Booth.
After screening and control measures and now only 15% of the herds remain infected and should be free of the disease within a year. "We are particularly interested in the production and health improvements in BVD-free cattle," added Dr Booth. "We are anticipating improvements in calving interval and calf health where herds have moved to BVD-free status."
The south-west project showed that farms removing PI cattle in combination with biosecurity enhancements and vaccination were able to reach BVDV freedom. "It is possible to maintain this status," added Dr Booth. "Control measures should include routine surveillance on BVD-free farms and PI identification and removal on infected units."
"We are confident that we will have significant data early next year to show the benefits of BVD control."
Proof that an eradication programme is successful came from seminar speaker Christoph Goetz, European sales manager for livestock and poultry diagnostics company IDEXX.
"The Swiss BVD eradication programme was launched in February 2008 and in three years the disease is almost eliminated," said Dr Goetz. "They took a straightforward strategy to detect and eliminate PI animals and all dairy cattle - 1.6 million - were tested for the presence of PI animals using mainly ear notch samples. Different PCR tests and an ELISA (IDEXX) were also approved for use."
In phase two of the Swiss programme, new-born calves had to be tested within five days of age. Again ear notches were collected and tested. "About 600,000 calves are tested each year and this will continue until the middle of 2012 when phase three will kick in with routine testing to ensure the absence of BVD," he added. Diagnostics for the detection of BVD antibodies in blood and bulk tank milk will be used."
When the Swiss BVD eradication programme started PI prevalence was at 1.5%. By July 2011 this had dropped to 0.07%. BVD has practically disappeared from many Swiss cattle herds.
The Swiss programme is paid for by state funds and producers who pay about one third of the total costs through an additional fee when purchasing ear tags. A £225-per-animal subsidy is paid for eliminating PI animals.
"We now have a programme in Germany to identify and eliminate PI animals. New born calves and sale animals must be tested using either blood or ear notch samples but whole herds are not tested for the presence of PI animals as it has been done in Switzerland. And BVD vaccination is allowed in Germany, unlike Switzerland, and it is used in densely populated cattle areas."
Beef cattle that are not moved from one farm to another and are being shipped directly to abattoirs have not been included into the German programme.
"As PI prevalence is beginning to decrease in many areas, producers in Germany are starting to see positive impacts of the BVD eradication program and herds are becoming healthier."
More details on the papers given at the NML BVD seminar are available from Milk@nationalmilklabs.co.uk