WINTER is well and truly upon us and now especially is the time to be extra observant about the health and well-being of grazing horses and ponies.

Daily checks in the short daylight hours are vital to be able to call for veterinary help at the first sign of trouble.

One of the cases I dealt with was a pony reported by its worried owners to be lying down in a field, seemingly unable to get to its feet.

With a little history-taking, it seems that the pony had been lame for a few days and they hoped it would recover by itself.

Now things seemed to have deteriorated rapidly and attention was urgently needed.

On the way to a call like this, you tend, as a veterinary surgeon, to run through in your mind the likely possible diagnoses. Could it be laminitis? Or an unseen injury, even a fracture? This type of call tends to get priority as the animal could need urgent attention so on that day I diverted away from some more routine visits and was in the yard within 10 minutes.

On arrival, I found the pony lying in the paddock in front of the stables. The pony was hesitant to rise and when he did stand up, the problem was very obvious to me. It was a severe case of mudrash. The pony had four white socks and each leg was covered in scabs which were bleeding and there were deep sores at the back of all four fetlocks and pasterns. My client was alarmed that he had not noticed this condition developing. There had been a lot of rain and the paddocks were wet and mucky.

He asked how could this have happened and why did it happen to his pony?

I decided to explain all the facts about mudrash to my client so that he could better understand the situation with his pony.

BACTERIA

Mudrash is a skin infection seen on the legs of horses, usually on the white haired legs associated with pink skin. It is caused by an organism called Dermatophilus Congolensis. This bacteria is found in mud and can survive for years. It can enter the skin through any cut or defect in the skin’s surface.

Once inside, it multiplies and spreads rapidly causing heat, swelling and pain. The body’s immune system reacts severely to this invasion which results in serum and pus infiltrating the area and eventually oozing from the skin.

This causes matting of the hair and as the sores spread, scabs form covering the sores. The scabs contain the organism. As the scabs fall off, the hair is lost and the legs become hairless.

This makes it easier to see the problem. The infection spreads rapidly, mainly affecting the backs of the pasterns and fetlocks.

When horses are grazing outside in wet, mucky conditions, the skin becomes soft and more easily damaged.

Any break in the skin is enough for the infection to enter. The legs can swell up and lameness can be severe.

In extreme cases, cellulitis can develop. In most years it is a winter condition. However mudrash can be seen in the summer months as well, particularly in prolonged wet spells.

Some horses are more prone than others to mudrash and there may be a genetic element to their susceptibility.

CLEANING AND TREATMENT

To treat the condition, you need to clean the legs with a good disinfectant such as Hibiscrub. It is best to use warm water and endeavour to soak and soften the scabs and try to remove them carefully.

The legs will need to be washed twice daily. After washing, they should be dried thoroughly even using a hair dryer. Next and only when the legs are dry, should an antiseptic cream be applied e.g. Sudocream.

There are dozens of treatments, creams and ointments on the market for mudrash probably indicating that no single product works magically.

In severe cases, it is necessary to treat with antibiotic injections. Penicillin is the one of choice. This will need to be injected for five-nine days. The key to effective treatment is the removal of the scabs so that the treatments can act directly on the infected skin. Most cases respond well within three weeks.

The basis for prevention of mudrash in the future is to keep the legs as dry as possible.

This can be difficult in the wetter months of the year when horses are outside. Barrier creams can be applied to prevent the skin from becoming too wet.

These creams are oily so the water will tend to be repelled by them.

PREVENTION

In wet months when horses’ legs get wet and muddy, you should:

With patience and correct veterinary advice, mudrash is treatable and can be effectively prevented from recurring. In this case, the pony was treated successfully and had healed within three weeks.

Denis Doyle MVB MRCVS is a veterinary practitioner in Wicklow town and is a member of the Equine Group of Veterinary Ireland

Email: hq@vetireland.ie

Telephone: 01-4577976