Foot warts can be a chronic problem, expert says

Overland Park, Kan.-

Even with treatment, digital dermatitis or foot warts remain a chronic problem for many dairy herds.

Steven Berry, DVM, dairy health and management specialist at the Universityof California-Davis (UC-Davis), explains, "Research shows that up to60 percent of cows that are successfully treated for foot warts have a recurrencewithin seven to 15 weeks." Berry adds that this level of recurrenceisn't surprising, because animals remain in the same environment where theycontracted the disease.

Berry recently made the remarks in a meeting with about 100 foot trimmersin Wisconsin Rapids, Wis. In a UC-Davis study, 22 cows with foot warts weretreated with two antibiotics. After three weeks, warts were visibly healedin 18 of the animals. But 10 of these cows still had microscopic evidenceof lesion activity in their hooves.

Three factors play an important role in the prevention of digital dermatitisincluding environment, bacteria and management, Berry explains.

Foot warts, or hairy heel warts, are associated with wet, muddy conditions.In a UC-Davis study to determine how the disease is transmitted, researchersfound that foot warts only occurred when hooves were exposed to constantmoisture with low exposure to air.

UC-Davis researchers have isolated three types of Treponema bacteriain hooves infected with hairy heel warts. Treponema are anaerobic bacteria,therefore hooves caked in mud are far more susceptible to foot warts.

Management: frequent alley scraping and other manure management techniquescan help control foot warts, as well as routine copper sulfate footbaths.

Berry suggests isolating purchased animals for at least a month becausethe disease is believed to have a three-week incubation period.

With a grant from the California Milk Advisory Board, UC-Davis is currentlyconducting field trials with Treponema Bacterin, a vaccine for foot wartprevention from Novartis. Results from the five-location trial are due laterthis year, Berry adds.