Monday, January 13, 2014

A Preventale winter Problem: The Subsolar Abscess

 A preventable mid-winter problem: The Subsolar Abscess

This time of year I commonly see horses with lameness caused by subsolar abscessation. It seems like part of the winter cycle - we discussed what you can do to avoid cold related problems during our December crazy cold spell, then we talked about the dangers of icy footing around Christmas time, and now as mid-winter arrives the preventable problem of the season is the foot abscess. 

Here is what happens: First, horses are likely to be confined to smaller areas and get less exercise (and therefore less grooming) during the winter months.  Second, weather conditions make manure collection and disposal challenging, so pens tend to be dirtier than normal.  Third, freeze/thaw cycles, urine spots and collected manure all contribute to the creation of deep, wet, bacteria rich footing in our horses pens.  Moisture and bacteria enter the sole through small defects that occur naturally.  But now the foot may not be getting picked out daily, the sole never dries, and bacteria migrate through the horny sole and begin to replicate in the space between the horny, insensitive sole tissue and the deeper soft, sensitive tissues of the hoof.  The body tries to fight this slow growing infection by sending white blood cells to the area.  The white blood cells break down to form a gooey, black semi-liquid pus.  This pus spreads between the superficial and deep sole layers, building up pressure until one day your horse is suddenly extremely lame. 

As with all abscesses, drainage is the key to cure.  Subsolar abscesses are resolved by aggressively removing the overlying dead sole and exposing the infected area and underlying sensitive tissue to air.  The area is packed and bandaged for 7 to 10 days to prevent re-abscessation and allow the exposed tissue to cornify and begin the transition from sensitive to insensitive sole.  Antibiotics are not part of my routine care of subsolar abscesses, but tetanus vaccination status must be confirmed, and pain control with phenylbutazone is usually warranted. So your horse gets better, but in the mean time he/she experiences severe lameness, and you are out there in the freezing cold when you get home from work every night in the dark struggling to change the darn bandage!

The good news is these winter weather condition related abscesses are preventable!  Your job is to work hard to keep you horse's pen as clean and dry as possible, not to neglect regular farrier visits every 6-8 weeks through the winter, and to pick out your horse's feet thoroughly every day through the winter months.  Some of these slow developing winter abscesses, such as the one pictured above, can be deep and extensive.  Please be a good partner to your horse and pay special attention to foot care during the off season, and you can spare your horse this painful problem.

I believe that education is the key to evolution. I believe that animals are the key to compassion. I believe the learning never stops.

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