Tips to treat scald as farm cases escalate

Warm, wet weather is causes a higher incidence of sheep scald, vets warn.

Dry spells of weather, interspersed with heavy downpours, provide “perfect” conditions for the scald bug to flourish.

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Scald, which is also known as interdigital dermatitis, is the most common cause of sheep lameness.

There are several bacteria that causes it – one of which is Dichelobacter nodosus, which can lead to foot-rot.

Anything that causes trauma to the feet, like dry, stony ground or long grass, allows bacteria to penetrate the skin.


Treatment depends on the number of sheep affected. Individual cases can be treated topically using oxytetracycline sprays.

But if flocks are suffering from a large outbreak Ms Young advises foot-bathing with a solution containing either formalin (at 3% dilution) or zinc sulphate (at 10% dilution).

Be accurate on the concentration you are using because if formalin is too strong it can be harmful as opposed to helpful.

Ideally all lameness cases should be treated within three days to limit the spread of infection within the flock.


Avoid overcrowding and where possible locate water troughs on well-drained soils to avoid poaching of the ground.

If you are buying sheep, quarantine them for 21 days and foot-bath them [within this period].

If you don’t have a problem with foot-rot you don’t want to buy it in with other sheep.

Best practice when foot-bathing sheep:

  • Treat early to minimise spread
  • Gather sheep into a clean area
  • If practical, manage small groups to minimise spread
  • Make sure feet are clean going through the solution. Run them through water first if they have dirty hooves. It can be helpful if straw is included within the water because it’s abrasive, which helps to pull mud off
  • Stand sheep on a hard surface for one hour after treatment
  • Turn them into a clean field that hasn’t had stock on it for two weeks.