With the price of copper sulfate increasing and environmental concerns about copper levels in soils, many producers are searching for footbath alternatives.
However, there seems to be some confusion about what different products are doing, so it is time to review footbath goals.
Treatment or prevention
Let us be very clear. Footbaths are used for prevention not treatment of active, painful lesions. Lame cows with heel warts must be identified through locomotion scoring and then individually examined. Topical antibiotic therapy with a light wrap is the mainstay of treatment.
Think of foot bathes for the control of heel warts - similar to the use of teat dip for the control of contagious mastitis. It does not treat active infections, but it helps control the spread of infection from cow to cow. For that reason, in most freestall barns, footbaths must be used frequently – but there is farm to farm variation depending on hygiene.
Leg hygiene determines frequency
The more manure contamination of the lower leg, the more frequently we must footbath.
While some farms with excellent leg hygiene may use a footbath only once a week, others must footbath 5-7 days per week.
Use a hygiene scoring assessment to determine frequency. Score the manure accumulation on the hoof and leg of the rear feet on a four-point scale where 1=clean, 2=splashes, 3=plaques but hair visible and 4=plaques and no hair visible.
In herds with fewer than 25% of cows scoring a 3 or 4 score, footbathing can be done as needed. Heel warts are rarely a problem. Conversely, where herds are >75% 3 and 4 scores, then footbathing is probably a necessity 7 days per week.
Typically foobaths can be run twice a day, even in 3 times a day milked herds, BUT if the footbath is not in use, cows MUST be able to bypass it and not walk through a pit of manure. If there is no way around the bath – put something in it!
Cows appear to be more susceptible to heel wart infection in early lactation, so the final footbath frequency for groups WITHIN a herd can be manipulated. For example, the close up group can be footbathed once a week if we push cows through a bath at least twice. Early lactation cows should be footbathed at the maximum recommended frequency determined by leg hygiene. Late lactation cows may be footbathed at 50-75% of the target frequency in order to save on chemical costs.
Footbath location and design
Footbaths are frequently poorly designed and located. The best places for them appear to be in transfer lanes between the holding area and the pens and in the return lanes on either side of the holding area. In return lanes, make sure that the bath is located two thirds of the way down away from the parlor so that cows do not create a jam leaving the milking area.
Twin baths are optional. If a wash bath is used it should be located 4-6 feet in front of the treatment bath. Wash baths immediately adjacent to treatment baths allow for carryover of wash solution into the treatment bath as the cows splash though – diluting the active concentration of chemical.
The treatment bath should allow for at least a 5 inch depth of solution and be at least 8 feet long, preferably 10 feet. Width is determined by the width of the alley. The floor of the bath should not be excessively rough, but it should be non-slip.
Chemicals – cleaning agents vs disinfectants
Footbath solutions may help clean the foot of manure and disinfect the interdigital space. Do not confuse the two actions.
Solutions of hand soap or rock salt are probably primarily cleaning agents – they loosen manure on the foot and allow oxygen to get to the interdigital space. They can be used in the footbath program, but should probably not be the only chemicals used. Other chemicals are disinfectants. These are the traditional copper and zinc sulfates, formalin, quaternary ammonium compounds and a range of commercial products. Footbath programs should always contain one or more disinfectants. Antibiotics should only be used in outbreak situations where the infection rate must be brought under control – in these situations Lincomycin or Oxytetracycline can be used extra-label UNDER VETERINARY DIRECTION for a short period of time (3-6 milkings) and then a disinfectant can be used to maintain the improvement.
In designing a footbath program, cleaning agents can be used for one third to half of the time, then disinfectants can be used for the remainder. Most chemicals are active for around 200 cow passes – formalin may last 300 cow passes, some chemicals last only 150 cow passes. Activity will also depend on the amount of manure contamination.
Replacements for copper sulfate
There are two approaches to take;
- Use copper sulfate, but use less of it. We can do this by substituting a cleaning agent for some of the baths instead of using copper – liquid hand soap or rock salt are commonly used, OR we can use additives to the copper sulfate so that we can lower the effective concentration. Some additive products contain acids that allow the copper to dissolve and become more active, reducing the effective concentration to around 2-3% instead of 5-10%.
- Use something else instead. There are lots of other chemicals to choose from. The cheapest is probably formalin BUT be careful. This is a carcinogen and very careful handling is required. Additionally, formalin may not be legal for use in your area. Use of the chemical on dairy farms is probably difficult to justify, but it is effective. If formalin is used, use a step up program, such as 2% week 1, 3-4% week 2, 5-6% week 3, then return to 2% for control.
There are a number of commercial products that appear to be efficacious, but controlled research data is minimal. Zinc sulfate is a viable and efficacious alternative, but it dissolves poorly, especially when used at the preferred 10% concentration. Liquid zinc chloride is much easier to handle on farm and there are good reports of efficacy in the field.