Central Oregon Dressage Society

Wet Weather Medical Conditions

 

Wet weather can make horse housekeeping a tough chore here in the Northwest. Paddocks and pastures turn into muddy quagmires, and it becomes impossible to keep them clean, much less dry. Horses' coats get soaked through, and sometimes don't dry out for days on end, and the mud cakes on their legs up to the fetlocks. These environmental conditions predispose to several types of medical problems in horses, including hoof abscess, "scratches", and rain rot.

Hoof abscesses form when bacteria gain access to the inner, living tissues of the hoof, and begin to proliferate, causing a buildup of purulent material (pus). They are immensely painful to horses, because as the purulent material builds up, it creates pressure and inflammation in the sensitive lamina of the hoof. This is akin to having a festering splint trapped under your fingernail. Abscesses are more common when conditions are muddy and wet, because the liquid muck penetrates through tiny cracks.

Treatment of abscesses usually requires a thorough exam of the sole to determine where the abscess tract is located, and then the tract can usually be pared out to release the purulent material. Sometimes it isn't possible to find the tract, and the foot must be soaked for a few days to bring the abscess to a head before it can be pared out. Antibiotics may be necessary, depending on the extent of the abscess. The foot must also be kept clean and dry for several days to weeks after the abscess is relieved, because the sensitive tissues of the hoof have been exposed and need to heal over with granulation tissue

before they can tolerate exposure to a dirty environment and resist further infections.

"Scratches" is the lay term for pastern dermatitis. It is also called "greasy heel." In this condition, the skin of the pasterns and heels develops a superficial infection with bacteria and sometimes with fungus. "Scratches" is most common in moist, muddy conditions when the pasterns are coated with mud for days on end. It can be difficult to treat, especially if it becomes extensive, and horses can be very painful to the point of non-weight bearing in some cases. Treatment requires thorough clipping and cleaning of the area, removal of scabs, and bandaging with topical ointments. In severe cases, oral or injectable medications may also be necessary.

Rain rot is another type of skin infection that occurs not on the legs, but on the topline, back and haunches of horses. The name is apt, because the bacteria that cause rain rot require very moist conditions, and thus the disease is most common in the rainy season in wet climates. The treatment is similar to that for "scratches", in that hair and scabs must be removed. A course of penicillin injections are often used to treat rain rot, as the bacteria that usually causes it, Dermatophilus congolensis, is sensitive to penicillin.

For all of these conditions, as with many medical conditions, prevention is key. Digging ditches to help drain water away from paddocks and providing a good layer of gravel under the footing improves footing greatly. If you can't improve the whole turnout area, pick a high area and improve it to allow the horses a dry area to stand. Bring horses in for a thorough cleaning and dry out session at least weekly, and inspect their skin and hooves thoroughly to detect any problems early. Keep feet well-trimmed to prevent cracking and overgrowth that predispose to trapping of mud and thus abscesses. Pick them out as frequently as possible, and treat with Koppertox or tincture of iodine to disinfect and dry them out. And remember, summer will come eventually!