As the wet weather continues and fields become more muddy we are seeing an increasing number of cases of mud fever in horses.
Mud fever is also know as pastern dermatitis as it tends to affect the lower limb. It is caused by the bacterium dermatophilus congolensis, which thrives in muddy conditions. This bacterium is a normal inhabitant of the horse’s skin, but when the skin is subjected to prolonged wetting or damage it can cause infection.
Factors predisoposing to mud fever include damp, mild conditions, standing in mud or soiled bedding, constant washing of limbs without drying, skin trauma, white limbs possibly associated photosensitisation damage and chorioptic mange infestation.
The area around the pastern develops crusts which adhere to the hair. Underneath, the skin is inflammed and may ooze. Skin cracks may also be evident.
Treatment involves keeping the horse clean and dry. It must be stabled. Bacteria live underneath the crusts therefore treatment involves removing the scabs. They may need to be softened with warm, soapy water. This can be painful for the horse and in severe cases they may need sedating. Once the area is clear the skin should be cleaned with an antibacterial solution, such as dilute chlorhexidine (hibiscrub) or iodine. This should be left for 10 minutes, then rinsed and and the skin dried. Once dry a moisture repellent cream should be applied, such as sudacrem. In severe cases systemic antibiotics may be required.
There are ways to reduce the frequency and severity of cases. Ensure that heels and pasterns are cleaned and dried thoroughly every day. Oily based barrier creams can also be used, vaseline is ideal. Another useful combination is 50 per cent baby oil and 50 per cent vinegar. The oil prevents the skin from cracking whilst the vinegar changes the pH so bacteria are less likely to grow. Test this on a small area 24 hours before full application. Waterproof leg wraps are an alternative to barrier creams.
Rotating paddocks ensures that the ground doesn’t become too muddy. Adding an area of hardstanding to the field can help.
It is important you remain vigilant for signs of soreness or scabs so appropriate treatment can be initiated early.