Dr. William B. Epperson, Extension Dairy Veterinarian, The Ohio State University
Footbaths are used as a tool to assist in control of infectious diseases of the claw and interdigital area of the foot. Foot rot and hairy heel warts are the main infectious diseases of the foot, and each respond only partially to footbath use. Both diseases are directly related to the level of environmental hygiene. Footbaths are generally viewed as helpful when disease is present at a low (<10%) level. When more animals are affected with disease, such as hairy heel wart, other methods must be employed for treatment.
Environments that are mostly free of manure buildup offer very little challenge to foot health, and therefore, require less footbath use and maintenance. If more than 50% of cows are clean (area between coronary band to ½ way up hock shows only small drop splashing of manure), then footbath use may be constrained to 2 days/week or much less. This might be typical of well managed tie stall housed cows. Many dairy farms with freestalls will not have this level of hygiene (though it can be achieved) and will require footbath use the majority of days, and maybe continuously. Obviously, a focus on frequent cleaning will improve hygiene, and will improve many aspects of health - foot, mammary, and reproductive.
If footbaths are necessary, consider targeting higher risk groups to limit costs. Early lactation cows seem most at risk for infectious foot disease, so intense use of footbaths for cows in this stage of lactation may be justified. Later lactation cows may require 50 to 75% the frequency of footbath use as for the early lactation groups.
Improving design and function of footbaths may improve their effect and limit the need for repeated treatment. Size the treatment bath to be at least 8 and preferably 10 feet long. Maintain a 5-inch solution depth. Locate the bath in the return ally, far enough away from the parlor to avoid a "cow jam" leaving the parlor.
If feet are clean entering the bath, the disinfectant solution has a better chance to work. A 2 stage footbath is an option, with the first stage footbath being water and detergent to clean the feet, followed immediately by the treatment footbath containing the active disinfectant.
When not in use, route cows around the footbath. If that is not possible, put something in the footbath. An empty footbath can create a manure pit cesspool that cows must walk through.
Using chemicals strategically can also limit disinfectant costs. Footbath solutions really have 2 potential functions: 1) assist in simple cleaning of the foot, and 2) disinfect the skin of the interdigital space. These are separate functions, and each contributes to foot health.
Soaps and rock salt are among those additives that assist mostly in cleaning. When dispersed in water, they help remove debris. This is helpful in exposing the foot to oxygen and inhibiting the bacteria that typically produce foot rot and heel warts. But, they have little disinfecting action.
Disinfectants include copper sulfate, zinc sulfate, formalin, and a number of commercial products. Antibiotics are sometimes used in footbaths when a heel wart outbreak is occurring. Antibiotic use in footbaths is an extralabel use and requires veterinary direction. Following a course of antibiotic treatment, footbaths are then maintained with a disinfectant. Most footbath chemicals are effective for around 150 to 200 cow passes.
Copper sulfate at 5 to 10% has been the most common disinfectant used in footbaths. Substituting a cleaning agent for copper sulfate on some days will reduce use. Additives can also be used to extend copper sulfate (check with your chemical/equipment supplier). Some acid additives claim to allow a lower concentration of copper sulfate (i.e. 2%) to be used. Ask your supplier about effectiveness of the products; some available products have little efficacy data available, so it may be difficult to predict which ones will work.
Zinc sulfate at 5 to 10% can be used to replace copper sulfate, but it is hard to get dissolved into solution when mixed with cold water. Again, there are commercial solutions containing zinc sulfate that alleviate this problem. Some commercial solutions, such as Double Action (West Agro, Inc.) have been tested and shown to be effective in footbaths, and may be used as replacements. Formalin (2 to 5%) is used in footbaths, but it should be handled with caution, as it is a carcinogen and irritant. While formalin does appear to be an effective disinfectant, its use in a food production setting is difficult to justify.