TheDairySite.com - news, features, articles and disease information for the dairy industry

TheDairySite Bluetongue Disease News

Autumn BTV8 Explosion Could Spell Disaster

15 August 2008

UK - An autumn explosion in BTV8 will make all unvaccinated stock vulnerable to infertility, abortion and stunted growth rates.

The National Beef Association has warned that the discovery of new, BTV8, bluetongue virus in unvaccinated cattle herds in The Netherlands, and the number of new outbreaks gathering in the Calais-Dunkirk area of Northern France, means that unvaccinated cattle on the British mainland are already vulnerable to attack from infected midges.

It says BTV8 first arrived in Britain on August 4th last year but was not discovered, and officially confirmed as circulating, until late September.

“Midge activity is approaching its peak and unvaccinated cattle (and sheep) are open to assault from infected midges that may have already been blown in from across the Channel or from midges that have bitten infected animals on English farms that were not identified as bluetongue infected premises during tracing and surveillance operations in 2007.,” explained NBA director, Kim Haywood.


*
"The cost of the vaccine is minimal compared with the damage that BTV8 can inflict through mortality, infertility or stunted growth rates."
NBA director, Kim Haywood.

”One of the biggest lessons learned last year was that the greatest number of BTV8 cases were discovered by surveillance (blood testing) and were not reported by owners because they thought their animals were sick.”

“All stock owners should be aware that no one involved in establishing this year’s protection strategies is prepared to bet that the virus is not already circulating.”

“And farmers who are in the PZ, and whose cattle are not yet vaccinated, should know that in the four weeks since the first new French case was discovered this summer another 4,000 were confirmed and current estimates are that infection on a further 1,500 farms has still to be identified.”

According to the NBA this means that only farmers who have already completed vaccination of their stock can feel safe and even those who have still to vaccinate cattle a second time, or who are waiting for them to acquire full immunity two weeks after their last jab, risk getting infection and consequently becoming an Infected Premise (IP).

“When new BTV8 is discovered an explosion of confirmed cases can be expected to follow immediately and farmers who then rush to vaccinate cattle will have a nervous six weeks wait before they can feel secure,” said Ms Haywood.

“In these circumstances it is better to feel safe than sorry. The cost of the vaccine is minimal compared with the damage that BTV8 can inflict through mortality, infertility or stunted growth rates.”

“It is immediately noticeable that vaccine uptake in Eastern and Southern England was above the 80 per cent minimum because these stockowners were close to last autumn’s BTV8 fire and could smell the smoke.”

“However purchases in the West Midlands and North have not been as fast and some vaccine that has been sold is still in the farm fridge even though spring calving cows are not yet safe from abortion, or premature birth, if they go down with BTV8.”

“Screening of vaccinated herds has revealed that the side effects are lower than those reported after using other, long established, vaccines on a routine basis and that the dominant cause of problems after BTV8 vaccination is poor handling.”

“Farmers in East Anglia whose stock caught BTV8 last year reported infertility in bulls, a doubling in the rate of abortion, stunted calf growth and a huge level of cost and hassle after being identified as an IP.”

“A national protection blanket is established if at least 80 per cent of cattle and sheep are vaccinated and midges have less infected animals to bite. But if farmers in specific areas turn their back on the BTV8 vaccine then all unvaccinated stock in that region, including their own, is at risk,” Ms Haywood added.

TheCattleSite News Desk


Partners


Seasonal Picks

Managing Pig Health: A Reference for the Farm - 2nd Edition