16 November 2001

Warm, wet October key to fears over lameness

By Hannah Velten

LAMENESS across all livestock species could rise above seasonal expectations because of this years particularly wet and mild autumn, making prevention a priority, warn vets.

The Met Office has recorded not only the warmest October since records began, but an average rainfall 59% above the long-term monthly average.

Despite reduced numbers of disease records submitted by vets to the National Animal Disease Information Service (NADIS), more cases of lameness are being reported than usual, believes independent vet consultant Tony Andrews.

"In damp conditions, permanently wet foot horn gradually softens, allowing penetration of stones and bacteria." Recent conditions have also been perfect for bacteria population explosion, says Dr Andrews.

However, Dumfriesshire sheep and cattle vet Ross Muir believes levels of lameness are no worse than usual. He is visiting sheep farms more often for movement inspections, so sees lameness which producers would normally deem unworthy of vet attention.

But Rose Grogono-Thomas, of Bristol University vet school, says foot-rot cases may increase. "Foot-rot bacteria cannot spread below 10C, so in current mild conditions a control strategy is crucial.

"Foot-rot is a contagious disease, particularly prone to spread through flocks at housing. Infectious stock should be separated and treated away from the main flock and vaccination three to four weeks before housing is a control option."

She recommends a 10% zinc sulphate footbath for sheep. "Formalin is caustic and hardens hooves, making pairing more difficult. After bathing, stock must stand on concrete until hooves dry then let them out to clean pasture.

"Although producers may be reluctant, culling stock after one failed foot-rot treatment is the most effective control strategy," believes Dr Grogono-Thomas.

The longer dairy and beef cattle are left out at grass the likelihood of digital dermatitis, foot-rot and white line disease cases increases, says Hants-based vet Andrew Richmond.

"Try feeding cattle in different places around paddocks to prevent stock standing in quagmires. Maintenance of tracks, and using compacted chalk, straw or second-hand belting from quarries in gateways is equally important to reduce stone damage to feet."

Formalin or organic acid footbaths must be routinely used to maintain condition of the foot surface of cattle and remove bacterial contamination, says Mr Richmond.

"Cattle must, however, be made to walk through water before going in to the footbath, allowing active ingredients to reach the foot surface." He recommends footbathing twice a week and repeating the practice after each 14 days.

Laminitis predisposes cattle to white line disease, making the importance of a balanced diet crucial, adds Mr Richmond. "Acidosis in the rumen reduces blood circulation in the foot causing laminitis. Splits in the hoof then allow dirt in."

Slurry heel is caused by ammonia eating its way into the soft heel area of the foot. "Cubicle housing and yards must be scrapped out often to avoid cattle standing in slurry. In straw bedded housing keep replenishing clean, dry straw," advises Mr Richmond.

Unfortunately, lameness in outdoor pigs is hard to prevent, says Suffolk-based pig vet Roger Harvey. "This season is no worse than previous years for lameness caused by sand cracks, scald and inflammation between the claws.

"The ideal treatment is to remove pigs from the environment, but this is impractical. To alleviate damage to feet, straw beds covering particularly wet paddock areas provide drier standing away from stones and mud," advises Mr Harvey. &#42

LAMENESS

&#8226 Foot-bath routinely.

&#8226 Isolate infected stock at housing.

&#8226 Provide dry standing.