VETERINARY surgeons have a vital role to play in ensuring that livestock farmers are fully informed of the consequences of bluetongue and the way in which the disease can impact not only on their animals’ well-being but also the financial health of their businesses.
The harsh realities of bluetongue are, as yet, unfamiliar to most UK livestock farmers. But the more they can learn about the range and severity of consequences, both immediate and longer term, the more likely they are to make an informed decision about vaccinating their livestock.
The experiences of farmers whose livestock have already been challenged by bluetongue virus clearly demonstrate the impact it can have on productivity and financial performance.
Jakob Pustjens, a dairy farmer and agricultural consultant in the southern Netherlands, had one client who saw the average annual milk yield per cow decline very quickly during the 2007 bluetongue outbreak, from over 7,500 litres to less than 6,000 litres.
On another high-performing unit, the average daily yield fell from over 40 litres to under 10 litres in less than a month. A quarter of the herd eventually had to be slaughtered and even when the farm was declared free of the disease it was subsequently difficult for them to get milk production back above 25 litres per day.
Over 20% of Jakob’s own dairy cows had problems with their feet and difficulty walking. Milk yields dropped from an average of 30 litres per day to 28 litres, cows were more difficult to get back in calf and the herd’s calving index slipped from 390 days to over 410 days.
Economically, Jakob believes that his own herd got off very lightly compared with many other farms in his region.
“Milk production has since stabilised and our calving index has improved, but the disease still cost us between €10,000 and €15,000. The livestock industry as a whole in the Netherlands had apparently lost around €81 million in total by the end of 2008 as a result of bluetongue.
In the UK, one of the first dairy herds to be affected in 2007 reportedly suffered losses of around £30,000.
Losses in Essex
Also during the UK outbreak, Essex beef farmer Philip Ratcliff ’s suckler cows and calves were noticeably knocked back by the disease, with milk yields and growth rates adversely affected. Philip also lost twice as many calves as in a normal year as a result of late abortion which he believes is a longer-term, knock-on effect of the disease.
“Bluetongue cost my business thousands of pounds in both 2007 and 2008 through additional labour, higher veterinary costs, additional medicines, greater feed costs and increased calf mortality,” he said.
These farmers are left in no doubt about the need to vaccinate their stock against bluetongue, and it is important that their motivations for this are communicated to those livestock producers who are still undecided about vaccination.
Vaccination is vital in order to protect both individual businesses and the viability of the entire industry. Sheep, in particular, can quickly succumb to the disease in large numbers.
Professor Peter Mertens, a research leader at the Institute of Animal Health, provides one example: in Belgium in 2007, vaccination did not take place and roughly 20% of the national sheep flock was killed by the disease in just two months during the late summer, when the biting midges that transmit the virus are most active. In this case, the disease killed approximately 50% of those sheep showing any clinical signs of infection.
“The economic consequences of a bluetongue outbreak should not be underestimated by the livestock industry and more can still be done to improve farmers’ awareness,” says Brian Rice, veterinary adviser at Merial Animal Health.
“Vets are the primary and most trusted source of information and, by highlighting the longer-range business consequences of bluetongue as well as the physiological impact on the animal, we can help to improve understanding of the significant risk bluetongue presents.”