12 September 1997

Practical solutions to break the cycle of TB transmission

TB INCIDENCE in cattle is highest in the south-west of England and Ireland due to the climate.

Elaine King of the national federation of badger groups told a first European Vertebrate pest management conference, staged last week by the University of York and MAFFs Central Science Laboratory at Sand Hutton, York, that climate has a strong influence on the transfer of bovine TB from badgers to cattle.

Climatic conditions which were highly correlated to the number of herd breakdowns the next year had been identified as high rainfall, low ultra-violet sun hours and low temperatures.

Cattle were most at risk from cross infection during a six-week period each spring when the above conditions – mild, damp weather – coincided with turnout to grazing. Cattle were probably infected due to exposure to badger urine containing the TB bacteria, which would, at that time, be very infectious, she said.

But it should now be possible to prevent transmission from badgers to cattle by identifying high risk conditions and making adjustments to management practices.

As badger latrines had been shown to be concentrated on field boundaries, she recommended fencing off hedgerows at critical times.

It might also be possible to adjust the timing of cattle turn out to pasture and to take a look at stocking densities.

"Various management strategies must be tried to see if we can break the cycle of transmission," she said.

Cattle are most at risk from cross infection of TB from badgers when the weather is mild and damp.

FARMMANAGEMENT

&#8226 Fence off hedgerows at critical times – six weeks each spring.

&#8226 Adjust timing of turnout to pasture, and stocking densities.

&#8226 Two strand electric fencing – cost effective badger management.