Lameness is the second highest culling reason in the U.S. behind mastitis. Humid conditions during spring predispose to this problem. During the first hour of exposure to water the hoof gains one-third of the total absorbed. Excessive water softens hooves, easing access of infectious agents such as the one responsible for hairy heel warts (digital dermatitis). This is one of the leading lameness causes with 62 and 49 percent cases in bred heifers and cows, respectively.
Keeping hooves as dry as possible should be a priority. Using footbaths and hoof trimming can help decrease hoof injuries and infections. Hoof trimming helps identify hoof disorders and maintain hoof health. When not trimmed regularly hooves grow unevenly, with weight-bearing changes that damage the underlying hoof tissues. Eighty percent of the dairies in the U.S. hoof-trim their cows. How often is needed usually depends on the number of cows to be trimmed.
Footbaths should be a prevention rather than cure of an infectious lameness problem. Farms where cows spend more time with their hooves exposed to wet surfaces should use the footbath more frequently, at least twice a day until conditions improve. Cows with compromised immune systems such as immediately pre and post calving seem to be more at risk. Footbaths should be a bio-security measure for the farm whenever new animals are incorporated.
Copper sulfate is the most common medication added to footbaths. It should be added at 2.5 to 5 percent or 26 pounds in 62 gallons of water. The solution should be replaced often as the accumulation of organic matter will inactivate it. Rather than going by specific dates check the water color which should remain bluish.
Formalin is a solution of roughly 37% formaldehyde that can be hazardous to human health, causing irritation of eyes, nose, and throat, and burning the skin. These problems can also happen in cattle if not used at the right concentration.
Antibiotics are oftentimes used where bacteria are suspected or confirmed. Lincomycin and Oxytetracycline can be used for a short period although their use should be supervised by the acting veterinarian.
Additional information on this topic can be found in the SDSU extension publication: Wet Weather: Lameness and Mastitis.