DHJ:: “Doc– What's a Good First Aid Program For a Foundered Horse?"

"Doc – What's a Good First Aid Program For a Foundered Horse?"
© A.J. Neumann, D.V.M.
published in The Draft Horse Journal, Autumn 2001

“Poll evil” is a very archaic term applied to a condition found in some horses, which originates in the atlantal bursa which is located in the tissues at the top of the neck area, behind the ears and just to the rear of the skull. This is the area on which the top of the halter or the crown of the bridle rests when they are placed on the animal’s head. The term in itself is very antiquated. I can trace “poll evil” back as far as 1731 where it appears in a book, which contains writings about causes and treatments concerning certain conditions of the horse. If one breaks the term in half, we can readily understand the word “poll” being used because that refers to the area where the condition is found. We use that term today in referring to the “poll” of the horse or mule. How the word “evil” got in the term I have no idea, but I’ll bet it goes back a long long way in time. My own idea for the use of “evil” in naming the condition goes like this:

Many years ago, before the advent of modern drugs and antibiotics for use in the horse, this affliction was extremely difficult to treat. It therefore could be construed as an “evil” thing because a horse suffering from this condition often was extremely hard to handle and became very mean, even after the condition was brought under control and healed. The same is true today. Therefore, we could say the horse acted and became “evil” when its poll was involved in this fashion. Anyway, that’s my speculation as to the origin and use of the term “poll evil.”

The very first symptoms usually reported by the herdsman or owner of an animal suffering from a poll evil in its early stages will be a slight swelling, either on one side or both sides of the area on the top of the head, immediately to the rear of the ears and skull. The area will be warm and very “tender” to the animal when touched. Often the party will say, “The horse doesn’t like to be bridled or haltered and he throws his head when I touch his poll!” These symptoms occur early on and are often missed if the horse or mule is not handled almost daily.

Photo to the right: This is a picture of a poll evil on a 4 year old mare in August 2000. Another veterinarian had been treating it and this is what I inherited. He was deathly afraid of her as her poll was very painful to the touch. The bursa and necrotic tissue was draining through two fistulas on the bottom side. You can make out the two points of drainage. They twitched the mare and he reached over the top of the stall and made an incision on the top of the poll evil. Nothing came out. So he placed two sutures in his incision and called it quits.

Usually the condition is noticed when someone observes the horse standing with its head and neck extended and is very reluctant to move the head or flex the neck. Sometimes there is enough pressure on the ligament between the axis and the atlas that nervous symptoms such as staggering and partial loss of control of the front legs will be seen.

Often, examination of the poll at this time will reveal drainage of fluids or “pus” from several fistulous tracts located on one or both sides of the area. This is usually accompanied by tissue swelling and evidence of pain when the swollen tissues are touched or probed.

At this time the patient becomes so sore and sensitive that there is a great danger the animal will develop disagreeable habits such as rearing, striking and throwing the head. These habits or vices once developed, will persist long after the poll evil has been cured and the affected area is returned to normal.

When the animal has reached this stage of the game, it is imperative to get someone who can take care of the condition immediately or often the horse or mule is ruined for haltering, bridling, or just plain handling near the poll, for many years to come.

So what’s going on here? As simply as I can explain it without getting bogged down in a lot of anatomical terms, which would scare you off, it goes like this:

There is a big ligament, which goes from the area of the withers to the base of the skull. Forget about it’s name. It provides support for the head. Right on top, to the rear of the skull, under this ligament and on top of the bone called the axis, is a bursa named the atlantal bursa. Its job is to act as a cushion or shock absorber between the top or dorsal part of the bone and the ligament, which passes over it.

This little bag of fluid can become infected or bruised with a resulting inflammation of the bursa walls. If the irritation causing the swelling continues, the walls will thicken, degenerate and eventually necrose, or rot away. As the bursa walls thicken, it tends to penetrate the surrounding soft tissues and expand until eventually it ruptures. If it is not infected at this point, it will become so as soon as a tract is established to the outside.

The cause of the majority of these cases is infectious. It was found that the organism causing brucellosis in cattle, hogs, sheep and humans was the primary agent involved along with another, called Actinomyces Bovis. These two classes of bacteria caused a good many cases of so called poll evil and fistula of the withers. So it has been recorded that with brucellosis eradication in cattle and hogs, the number of cases of poll evil and fistulas of the withers in horses and mules has also declined dramatically.

But this is not the end of the story. There are other causes and today the numbers of poll evil cases are again on the increase. These other causes are blows to the upper portion of the neck by the horse striking its head against poorly designed hay feeders, beams of the ceiling, low doors, and low clearance horse trailers.

The greatest cause today I see is the constant chafing from a nylon halter across the poll of a horse. Many people rarely take the halter off their horses. They buy nylon halters and turn their horses out and leave the halters on. Just take one of these halters and feel the edges on the straps, especially the one going over the head. It will feel just like the teeth on a saw blade. As the animal grazes and moves about in all kinds of weather, the top strap of the halter works back and forth on the poll, eventually irritating the skin. The animal is tied, with the same halter, of course.

In time, we see some swelling of the poll area, some bleeding and eventually we see the ligament and the bursa become involved. Before we know it, old George is tender to the touch and doesn’t want to be tied or handled about the poll. About this time, somebody checks up behind his ears and his neck and, low and behold, they find under the halter strap is a stinking mess with blood and pus present. We have an old–fashioned poll evil in progress.

A lesson can be learned here: Never turn a horse out with a nylon halter on its head. This is especially true of the foal. A foal can get its foot into a halter, cast itself, break its neck or twist its neck in such a fashion it has to be put down. Add to this the inquisitive quality of a foal and it will soon have its halter caught in all manner of obstacles resulting, usually, in a “hung–dead” youngster.

The older horse with the nylon halter will reach over a gate or fence, hook his halter on something, fly back, and hang himself, break his neck or tear out the gate or fence and get his legs, feet and body into it with a resulting mess of injuries. I know, because I treat them and hear the horror stories all of the time. When these things happen to horse owners, they are not willing to talk about the accidents in public. Often the only people aware of the problem are members of the immediate family and the veterinarian when one was called in.

Why do we turn out the adult horse with a halter on? It’s to catch him much faster, easier, or just to get him caught at all. So why not put an old leather halter on him or one you’ve made out of some discarded hardware, old leather and a handful of rivets. It will work to catch old George but he’ll go right through it if he should happen to get hung up someplace.

And again, just in case you’ve forgotten, I think you are a fool to turn a foal out haltered, unless you don’t mind it choking to death or breaking its neck.

So how can we treat this poll evil, which we have just discovered on old George? First of all, remove the halter and keep it off. Next, clean the area with peroxide, not water. Clip off any mane hair, which could get involved.

If the area is just swollen, which means we have caught it early, put ice packs and some diluted DOMSO solution on the swollen tissue. You might give a daily dose of penicillin or another antibiotic to the victim for a few days. If you are lucky, and drainage of pus does not occur from the area, this will suffice to bring the condition under control.

However, usually an infection has already set in and there is a purulent discharge coming from one or more fistulous tracts. Then you will have to resort to antibiotic therapy as well as hot packs and surgery to remove the affected, infected and necrotic tissue.

Today, the surgery is not difficult. I operate these cases standing, on the farm or at the stables. The patient is placed on antibiotics at least 24 hours prior to surgery. Hot packs are placed over the area as often as possible during that 24 –hour period so as to localize the infection.

I sedate the animal and leave it standing. The surgical area is infiltrated with lidocaine and the surgery is performed to remove all the fistulous tracts and necrotic tissue. The area is then packed with a neomycin or iodine pack and the skin is sutured over the pack. I really prefer the iodine pack.

The pack or packs are removed in 48 hours and the area is left open somewhat so drainage can occur. The area is flushed twice daily with a neomycin solution. At 10 days, any stitches in the area are removed. Healing usually will be complete in 10 to 14 days.

During this time, the patient has been on an antibiotic program, which is given orally.

This surgical procedure has worked quite well for me, as rated against the old–time way of general anesthesia for the afflicted horse or mule.

When I was in vet college during the ‘40s, it was not unusual to have several draft horses with poll evil in the clinic at one time. So, as students, we had the opportunity to see and treat quite a few of them. Today, many younger practicing veterinarians in a general practice have never seen nor even heard of a poll evil on any breed of horse. I find many of these veterinarians are at a loss on how to recognize or even treat these cases, and that is the very reason I get to treat a number of them.

When checking a horse with the intention of buying it, a very good practice is to place your hand at or near its poll. If it reacts by throwing its head or trying to strike, you should be aware of the fact the animal will be difficult to halter or bridle. The causes of this vice are many but just perhaps, at one time it had a poll evil.

In retrospect, how many of you can remember seeing a horse or two with a padded halter strap on his poll? Now you know the rest of the story! That animal probably had a problem up there!