Dutch dairy farmer shares bluetongue nightmare

Up to 70,000 litres of milk lost (with production still recovering) and long-term fertility issues caused by more abortions and mummifications – Dutch dairy farmer Guido Tuten continues to experience the effects of bluetongue.

His herd was infected in July 2007 but, as he told farmers at a series of meetings organised by Penbode Vets in Devon, the family’s 105 cows and 84 followers are still feeling the effects of BTV8. No wonder that Mr Tuten believes the cost of vaccination – albeit a voluntary expense – is nothing compared with the short and long term damage from disease. “We saw problems at calving, losing five calves to mummification which we don’t normally see, as well as an extra 2-3 abortions and I’m now having to find more heifers because we lost cows,” he told farmers.

The Tutens’ herd is in the east of The Netherlands on two farms totalling 55ha of grassland and 9ha of maize. Production is normally an average 7,600kg/cow with a cell count of 150,000 cells/ml. Cows are vaccinated for BVD and IBR and there is a herd health programme for Johne’s, leptospirosis, salmonella and neospora.

When bluetongue first struck, Mr Tuten said that he saw crusts on noses as well as teats, early calvings and abortions. Milk production fell by about six litres/day and stayed down for 2-3 months. “Blood antibody tests showed that out of 12 cows tested, 11 were positive for BTV8 and four heifers out of seven. Our plan for 2008 is vaccination, but with just six million doses of vaccine for Holland we are prioritising heifers, then cows, then calves,” he said.

Vaccination is only part of the prevention plan, added Dutch cattle vet Marco Verhoef from the Veterinary Services Midden Salland. And farmers must focus on prevention because eradication isn’t an option, he warned. Regularly checking stock for signs of bluetongue, together with removing midge breeding grounds, to reduce the vector population and therefore the risk of disease, are both vital as is monitoring susceptible groups of stock, particularly pregnant animals. “Repellents, insecticides (pour-ons and ear tags) and reducing contact with midges at dawn and dusk didn’t work well as we were too late in the season when we started,” he said. “BTV will become an endemic disease and economics will determine the prevention plan. But don’t underestimate its effects.”

Mr Verhoef’s practice covers 300 dairy herds milking 31,000 cows, plus 9,000 head of beef cattle in an area of high livestock density. Yet, like many vets, he saw a range of clinical signs from none, to mild, severe – even death.

“The virus circulated in stock for a long time and we saw swollen lips, muzzles, ears as well as crusts and lesions on noses. Cows were depressed, unable to rise, drooling saliva and were lame.”

Other signs included diarrhoea, conjunctivitis, pneumonia and cows calving up to 14 days early, or aborting. In data gathered from the Netherlands, France and Belgium, Mr Verhoef said that in about 50% of cases there were crusts and lesions on the nose; conjunctivitis in 31% of cases; fever in 31% and purple teats with lesions in 21%. “Treatments are NSAIDs (non-steroidal anti-inflammatory drugs) to reduce inflammation and antibiotics to prevent secondary bacterial infections plus lots of TLC and easy access to water.”

However, even though cows can recover – usually within 10 days of treatment starting – there are long-term hits on fertility, milk yield and heifer growth rates. “In autumn 2007, we saw pregnancy rates down 50% and abortion rates up by 20-30%. Mummification occurred at all stages of pregnancy including calves born three weeks early. Service bulls became temporarily infertile and when we re-checked pregnancies in December, up to 10% of cows were empty or had mummified foetuses.”

Milk output fell on average 2-5kg/cow and this lasted for between one and three months. Herds have also been left with long lasting lameness problems (such as arthritis) and dealing with early-born weak calves, added Mr Verhoef.

Farmers attending the four meetings went away clear with the image that bluetongue disease is not only devastating at the time of infection, but for some considerable period afterwards too.  The call to vaccinate all UK farm stock was supported by all who attended.