What New Things Have We Learnt So Far?
- Affected carrier cows, especially those with active lesions on the foot, are the main reservoir for infection.
- There are fewer bacteria in the environment than we previously thought, so slurry is less important as a source of infection but it is implicated as a way of damaging the skin so bacteria are more likely to invade.
- DD infection on top of sole ulcers or white line disease can cause these to become non-healing.
- DD may also be involved in mammary dermatitis and teat necrosis.
What Can We Do To Reduce Digital Dermatitis?
Four control principles:
1. Reduce infection pressure by treating carrier cows with lesions to reduce the level of infection.
- Use mobility scoring to detect infection early – catch those score 2s!
- Segregate affected cows and pick up their feet: good equipment is necessary to do this quickly, safely and easily – “1 cow, 1 person, 1 minute!”
- Effective treatment – this is a topic that is still surrounded by lots of debate!
- Cleaning/hygienic drying and inspection of the foot.
- Oxytetracyline/chlortetracycline spray (Cyclo SprayR) of the lesion.
- Use of systemic, injectable antibiotics in more difficult cases.
- Use of non-steroidal anti-inflammatories (pain killers), where indicated.
2. Keep foot skin healthy – slurry management; keeping feet dry/ reducing slurry pooling, cubicle comfort; increase lying times.
3. Boost immunity – keep up good transition management/ nutrition and control other infectious diseases (such as BVD).
4. Watchbiosecurity–ifthereisDDonthefarm,havestrict quarantine periods, equipment disinfection and consider a closed herd. Although, if there is no DD on farm, be just as cautious in case a different strain is brought in.
Foot-Bathing & Bandaging
Non-antibiotic foot-bathing is certainly part of control on many farms and can reduce infection pressure. However, it must be done well if it is to be useful, otherwise it can dampen and damage the skin, increasing the risk of DD infection. There are no licensed products for antibiotic footbaths and very little evidence that they are even effective, so these should be avoided as part of our strategy for responsible use of antibiotics.
Bandaging is not required and can create wet, oxygen-lacking conditions that the bacteria that causes DD to thrive in (alongside causing significant skin damage). It is easy to leave bandages on for too long which can make skin conditions much worse.
References: NADIS website and ‘Update on treating digital dermatitis’ Owen Atkinson (Veterinary Times).