"Surface factors" is simply a term I use to refer to such things as saddle sores, girth rubs, scrapes, bruises, minor cuts, and skin conditions (specifically, rashes, hives, and scratches) on your horse. Surface factors on your horse might not seem too important at first glance, but in fact most of them can become serious if left untreated. Watch for them. If you apply simple measures when you first spot them, you can keep things simple and continue going on those precious trail rides.
Let's look at surface factors one at a time.
• Saddle sores. These are simply sores caused by saddle rub. Normal movement against a well-fitting saddle won't cause sores; however, poorly fitting saddles cause uneven pressure that damages the skin, and causes hair loss and raw spots. Obviously, the best thing to do in this case is to invest in a proper fitting saddle. If you're away from home and need a temporary fix, you can cut a hole in an old saddle blanket where the sore is located to reduce rubbing. (Don't use double padding-that will only make things worse.) You can also apply Nuskin (a topical that dries to produce a protective layer, much like a second skin) to the affected areas to help protect them; carry this product in your on-trail first-aid kit.
• Girth rubs. Like saddle sores, rubbing in the girth area also requires tack adjustment. First, you can try changing the fit and/or placement of your existing girth or cinch, but you may need to change the girth altogether. Always carry a spare girth on long rides, which can produce rubs even if your girth technically fits. If you don't have a spare, you can swap girths with someone else in your group. If no other girth is available, apply Nuskin or Desitin to the affected areas to protect them until you get home. At home, you can try covering your existing girth with fleece. If you still have a problem, you'll need to replace the girth with a better fitting, more comfortable one.
• Scrapes, scratches, interference wounds, and minor cuts.
Horses are pretty resistant to infection, so these types of superficial wounds will usually heal well on their own. Apply Furacin antibiotic ointment to anything open; otherwise do nothing but watch the wound heal.
• Rashes and hives.
These skin conditions will show up at the darndest times. Most of these afflictions are unexplained. Known causes include insect bites, a reaction to tack or topical chemical residues, an allergy to something ingested, and even airborne particles. Most rashes and hives will come on fairly suddenly, then gradually disappear over 2 to 12 hours. In mild weather, a bath will usually soothe the skin, giving your horse some relief from the related itching. Try to identify and eliminate the cause of the condition to slow or stop the reaction, then watch for signs of a more systemic (body wide) allergic reaction. These signs include dyspnea (difficulty breathing), swollen eyes, heavy nasal discharge (usually clear), and fever. Such signs can indicate a serious reaction. Severe depression can occur, which may lead to shock and even death. If you suspect your horse is suffering a systemic allergic reaction, call your veterinarian immediately. He or she can give your horse an appropriate antihistamine, which will usually remove the danger.
Last but not least is the big one, scratches (also known as grease heel and mud fever). This is the heartbreaker, the mysterious skin ailment that can close down your riding vacation. Volumes have been written on scratches; in short, it's a severe inflammatory condition that starts on the back surface of the pastern and quickly becomes complicated by the presence of bacteria, fungus, and yeast infection. Soon the horse is in too much pain to move well.
The condition is believed to be initiated by stress and stretching of the skin in the pastern area, which allows opportunistic infections to get started. It most commonly occurs in white-hair areas and in dry, alkaline soil conditions. Horses from the East traveling to the Southwest will commonly develop some degree of the condition.
How do you treat scratches? That's the $64,000 question, if you remember that old television game show. After 35 years of practicing veterinary medicine, I believe I've heard every kind of treatment out there, and the only thing I can say is they all start with, "Clean the area real well and apply..." Probably the most common end of that sentence is "...Desitin." Whatever you use, be sure to clean the area very well. Spend your efforts on prevention. Keep close watch on the skin under the long hair on the back of your horse's pasterns. Wash those areas regularly, and when the conditions are right for scratches, apply some kind of ointment before leaving on a ride and when you get back.