Nigel Cook recently reviewed current footbath practices used in dairy herds, questioned the mechanism by which footbaths function, and reviewed the available scientific literature for guidelines to assist in the creation of best practices for their use; the complete article is here. Based on that review, here is a summary of his recommendations for footbath design and management:
Footbaths should be used strategically as a tool to assist in the prevention of infectious hoof disease in all ages of cattle, from breeding heifers to lactating and dry cows. They are not a crutch for poor leg hygiene caused by poor pen design, infrequent manure removal, overstocking, or poor lame cow surveillance and treatment and they should not be relied on to cure active digital dermatitis lesions.
There should be a program in place to survey cows’ feet for early signs of active M2 lesions, and these cows should be topically treated independent of the footbath program (see Sara Pedersen recommendations here). The approach should therefore be to footbath as little as possible to prevent infectious hoof disease.
In herds endemically infected with digital dermatitis, the goal should be to keep active lesions to less than 5% of cows; the following strategy is recommended:
- A well-designed treatment bath should be used, correctly located to ensure smooth passage by cows and heifers.
The footbath should be 3.0 to 3.7 m long, 0.6 m wide at the base with a 0.25-m high step-in height, with sloped sidewalls to 0.9 m wide at a height of 0.9 m above the floor of the bath. Ideally, the bath should be located on a level surface. One side should allow access to the bath; the other can be plastic, stainless steel, or concrete with solid side walls to prevent cows seeing over the top. At this time, a separate wash bath cannot be justified, but the treatment bath may be used as a wash bath if the producer wishes to use water, salt, or a surfactant to help clean the feet. Ensure that there is easy access to the bath, with a straight walk through so that cows can follow each other easily. In larger herds, multiple baths can be positioned side by side to improve cow flow.
- A mixing tank should be located immediately adjacent to the footbath with a pump to transfer the agitated chemical into the bath.
Mixing should occur outside the footbath in a clean area where chemicals can be transferred safely by workers wearing appropriate protective clothing. The bath should be filled to a depth of 10 cm to ensure that the solution washes the interdigital space of cows passing through the bath. Empirically, refresh the solution each day, or after between 100 and 300 cow passes, whichever best fits with pen size and management on the farm. Bacterial count testing can be used to determine whether the bath requires refreshing more or less frequently. Solution pH should be checked. Where acidifiers are in use, pH of the bath should be verified so that it lies between 3.0 and 4.5 throughout the use period. Evidence of proliferation of digital dermatitis lesions may alert the farm to skin damage caused by solutions that are too acidic.
- Start using the footbath for 4 milking per week and adjust frequency based on outcome.
After 4 to 6 weeks, if infectious hoof disease goals are being reached, the frequency of footbathing can be reduced by one milking per week and performance can be reassessed. The adjustment may be repeated in order to find the minimum frequency where control is maintained. If goals are not being met, frequency can be increased, or antibacterial choice and concentration can be changed.
- Choose an antibacterial with evidence of efficacy for the prevention of new digital dermatitis lesions and foot rot.
Where copper sulfate can be used, it is clearly the first choice antibacterial to be considered. Concentration of copper sulfate should not be higher than 5%, and with use of an acidifier, concentrations of 2% to 3% may be used as long as pH is not lowered less than 3.0. Farms should monitor manure and soil copper levels routinely to limit lifetime loading. If soils or regulations preclude the use of copper sulfate, formaldehyde or another alternative product can be used in its place in a similar manner. Other products likely will not match copper sulfate for their curative potential, so it is essential to ensure that cows are being surveyed for new active lesions, and they should be treated individually. Evidence for skin damage, such as proliferation of digital dermatitis lesions, should be monitored as a warning sign that footbath chemicals are too caustic.