Scald
Scald, also known as interdigital dermatitis, is a common cause of lameness in sheep, particularly lambs. It is often seen during wet conditions, such as late spring or in housed ewes when straw bedding becomes wet and warm. Scald is caused by the bacterium Dichelobacter nodosus, which thrives in moist environments.
Symptoms and Diagnosis 🩺
The primary symptom of scald is severe lameness, which can interfere with grazing. Affected sheep may become sound within one to two days after appropriate treatment. The skin between the claws becomes red and swollen, covered by a thin layer of white discharge. Unlike footrot, there is no under-running of the hoof wall or sole.
Clinical Signs:
- Red/pink inflammation between the toes
- White/grey pasty 'scum' on top, which can smell
- Severe temporary lameness
Prompt treatment ensures there is no impact on growth rate. Delayed treatment can cause failure to gain weight or even weight loss.
Treatment 💊
Individual cases of scald can be treated using antibiotic aerosol sprays. When several animals are affected, treating all sheep in the group in a 10% zinc sulphate solution or 3% formalin in a footbath usually provides effective control. Antibiotic footbaths are not justified.
Steps for Treatment:
- Use antibiotic aerosol sprays for individual cases
- Footbath with 10% zinc sulphate solution or 3% formalin for groups
- Ensure sheep stand in a dry area after footbathing to allow the solution to dry on their feet
- Repeat footbathing at weekly or two-weekly intervals during the risk period
Prevention 🛡️
Preventing scald involves managing the environment to reduce moisture and ensuring good biosecurity practices to prevent the spread of bacteria.
Preventive Measures:
- Maintain dry bedding in housing areas
- Reduce stocking rates to prevent high moisture conditions
- Isolate and treat lame sheep promptly to reduce the spread of infection
- Implement a lameness control plan, such as the Five Point Plan, to manage and prevent lameness in the flock