Treating Leg Mange: Advice from Doc Hammill DVM

Bethany Caskey

Scratches and leg mange are characterized by very similar symptoms in equines but the causative agents and treatment of the two conditions are very different.

Scratches, also known as greasy heel, dermatitis, dew poisoning, mud foot or verucossa, can be caused by less than sanitary conditions and a resulting infection caused by bacteria, fungi, or virus. “Scratches” is characterized by slowly enlarging redness, crusts (scabs), and open sores on the back of the heels, pasterns and fetlocks. Unchecked this condition may spread even further up. The sores are painful and can cause lameness. Along with scabbing, you might find hair loss or areas of blood, fluid or puss. Most commonly the affected area is observed on the hind legs. Treatment usually consists of antimicrobial, anti-fungal and anti-inflammatory agents.

equine mange mite

Leg mange, also known as Chorioptic mange, foot mange, or heel mange is caused by a small insect called a mite. Chorioptes equi is the most common type infecting horses. These microscopic mites have eight legs and are closely related to spiders. Scab like lesions will be observed below the knees and hocks on the lower limbs with crusts and sores on the thickened skin. The wounds are caused by the mites puncturing the skin to induce fluid they can then feed upon. The mite’s feeding causes intense itching and affected horses will stamp their feet, chew their legs and rub their legs together in attempts to alleviate the itching. In long standing cases the skin often becomes severely thickened with deep creases, and permanent damage can occur. These mites do not transmit to or infest humans or other species and are exclusive to the equine family. There is a higher incidence of leg mange and scratches in the draft horse breeds, especially those with thick feathers such as Shires, Clydesdales and Brabants.

It is important to attempt to determine whether you are treating scratches, leg mange or both. The symptoms can be very similar and the two can exist concurrently. This is because once the skin is damaged by the mites it easily becomes infected by the opportunistic bacteria, fungi, viruses commonly found in scratches. If mites are present and traditional antimicrobial and anti-inflammatory treatments for scratches are used without treating with an insecticide, the mites will not eliminated and the process will start over. In the experience of Doc Hammill, DVM, it is common to treat draft horses for what is thought to be scratches without being aware that the underlying cause is leg mites. A microscopic exam of scrapings from the lesions is the diagnostic test used to confirm the presence of the mites. However, it is not uncommon for even multiple skin scrapings to come up negative, when in fact mites are present and causing the problem.    

Contrary to common recommendations, Doc Hammill advises not clipping the hair on the affected legs. His experience has shown clipping or shaving can make the skin problems worsen whether they are from scratches or leg mange.


In his 1886 book, Magner’s Standard Horse and Stock Book, the legendary horseman, Dennis Magner, states: “Clipping the hair from off the legs is regarded as a very serious cause of scratches, as it leaves the skin so bare that it cannot readily resist the effects of irritants of any kind as when protected by its natural covering; but the most common cause is the habit of washing the legs with cold water, and not drying them thoroughly afterward.  The sebaceous glands in the hollow of the pasterns become inflamed, their secretion is increased, the skin cracks, and discharges an ichorous matter.”


Doc first completely cured a case of leg mites in one of his own horses in the 1970s by experimenting with a powerful dose of an insecticide for mange in hogs that was later banned. So for years he was limited to the use less effective leg mange treatments and mineral oil in his practice and with his Clydesdale horses. Unfortunately, mineral oil and many other treatments typically only reduce mite populations and alleviate symptoms temporarily rather than eliminating the mites completely.

Injectable ivermectin is no longer licensed for use in horses due to some problems with infections at the injection site. However, many veterinarians have found injectable ivermectin products for cattle (such as Dectomaz) to be reasonably safe and very effective when used in horses, IF: (1) injected into the muscles of the thigh, (2) the injection site is surgically prepared, (3) absolutely sterile injection technique is used. Consequently, Doc Hammill recommends having a veterinarian administer the ivermectin injections. It is imperative that the hair be shaved off of the site and that the area is surgically scrubbed and disinfected before injecting. A new sterile needle must be used for each injection and it should touch nothing except the freshly sterilized stopper on the ivermectin bottle prior to the injection. Sterility is of utmost importance to prevent potentially dangerous infections. Many veterinarians will not administer ivermectin to horses by intramuscular injection since it is not licensed for use in equines. If you find one who is willing to inject your horse(s) with ivermectin they will likely require you to sign a liability release first.    

Thanks to the advent of ivermectin we now have the potential to eliminate Chorioptic mites completely and cure long standing and severe leg mange with a very specific treatment regime. In Doc’s experience ivermectin administered orally or topically will affect mite populations, but the results are often transitory. On the other hand, the cure rate is excellent when ivermectin is administered by intramuscular injection, and even better when accompanied by topical treatment with a specific flea and tick spray, and followed by rubbing mineral oil into affected leg areas between the series of injections.

Since treatment does not destroy mite eggs the ivermectin dosage must be repeated every two to three weeks, to not only kill the adult mites present initially, but to also kill the newly hatched mites before they can lay more eggs and re-infest the host. The timing is critical. Doc Hammill recommends a minimum of three treatments. The first treatment is to kill the existing adults, the second to kill the newly hatched and the third to eliminate any late hatching survivors.

For long standing, severe cases or cases resistant to treatment Doc includes a topical insecticide for dogs and cats called fipronil which is marketed as Frontline Flea Spray. Doc shies away from using insecticides in general, but spraying the legs once on the day of the ivermectin injection and once a day for two more days has helped cure some tough cases. Wear rubber gloves to rub the product into the hair and skin thoroughly. Whether you use the spray or not Doc recommends treating the legs with mineral oil between injections and for a few weeks afterwards.

If you are reluctant to use the injectable ivermectin regime your veterinarian might be willing to prepare a topical ivermectin, antibiotic, anti-inflammatory ointment for you. Wear rubber gloves and thoroughly rub the mixture into the affected skin areas 2 to 3 days in a row at intervals of two to three weeks. Treating the legs with mineral oil between ointment treatments will improve success. However, Doc warns that the results are often temporary except in some early and mild cases.

Applying mineral oil

Mineral oil is easily found and purchased from most general merchandise stores. To purchase gallons or larger quantities, the horse owner can obtain supplies from a veterinarian or a bulk oil distributor. Application is simple. Rub the oil into the affected skin areas of the leg twice a week initially and then once a week or every other week for maintenance after the lesions are healed and the itching gone. Plan a regular schedule and massage the oil thoroughly into the affected skin areas. A handy way to dispense the oil is to fill a plastic liquid dish soap bottle with oil and use it to squirt the oil onto the leg and rub it in. When the oil begins to soften the crusts and scabs, gently rub and pull them from the hair each time you treat the area. Accumulation of dirt on the hair can occur with the application of the oil but does not seem to be problematic. The oil seems instead to provide a necessary barrier for the skin against future dirt and moisture.

The key to success is to treat each leg thoroughly and regularly. There is no need to pick up the horse’s feet during treatment. Horses unwilling to have their legs massaged in this manner need to have some daily grooming and desensitizing by grooming further down the legs each day until they are comfortable with your hands on their legs and feet. If the horse is really difficult, you can loop a rope around the upper leg and rub it back and forth around the leg, gradually working up and down the leg until they can accept the touch. Switch to using your hands only after the horse is non-reactive to the rope.

The supposition is that the oil suffocates the mites by plugging their breathing holes. The oil is beneficial to the skin of the horse regardless if suffocation is the effect on the mites. Doc wipes the excess oil from his hands after a treatment onto the horse’s mane and tail to make them shiny and soft as well.

It is extremely important in the treatment of leg mange to treat all of the horses that have contact with one another, and to treat them on the same schedule. It’s also a good practice to check any new horses for symptoms before they come on to your property. A horse does not need to have visible symptoms to be carrying the mites and passing them on to other horses. Close contact between individuals is the most proven way of contamination. There are some claims that mites can live in the horse’s bedding for several months but those claims have not been proven. To be safe, removing bedding from the area is never a bad notion. Power spray the stalls a couple times during the treatment process if possible.  You can also clean the stalls and then let them stand for two to three months without horses in them to out wait any mites.

In summary, there are potential sources of bacterial and fungal infections everywhere. Scratches can appear as a single condition or be the result of a condition created by leg mites. Keep barns, corrals and legs as reasonably clean and dry as practical and use mineral oil as a grooming habit. Disinfecting grooming equipment with bleach and water occasionally can also help prevent the spread of unwanted skin conditions. 

Originally published in Rural Heritage, Spring ’08

Just What the Doctor Ordered

Bethany A. Caskey

“There are no shortcuts,” Doug “Doc” Hammill proclaimed at the beginning of his four-day driving clinic at the Natural Gait outside of Harper’s Ferry in northeastern Iowa. “Or should I say, there are no good shortcuts.”

His white hat, collarless shirts, gentlemanly manner and matter of fact statements were all in keeping with a country horse doctor from another century. Some may also consider the subject matter of his clinics a by-gone and lost skill as well.

The students were for the most part older baby boomers from all over the upper Midwest who were getting into horses again or first time horse owners who at last could satisfy the desire they had for a horse. Each had personal reasons for wanting to learn to drive, from the romance of it, to rounding out their horse’s education, to fine-tuning the driving skills they already had. The horses they had brought to the clinic ranged from a two hundred pound miniature to two thousand pound Brabant crosses.

Doc was joined for this clinic by his stepfather, Tom Triplett, who had spent 30 years with the forest service packing mules into the wilderness and driving teams.

Doc credits the horses and the mules as his greatest teachers as well as other talented horsemen and women. “The way to develop your own horsemanship is: if it works, hang onto it. If not, move on. The horse will find the holes in any technique.”

Doc’s approach is non-violent and less forceful than many old “traditional” ways of training a horse or mule to drive. He believes in training the human. “It is up to us with our reasoning abilities to learn how they learn. Our horses should trust us and respect us, but allow us to be the leader.” Doc’s teaching is a way of learning to interact and communicate with another intelligent being and not a list of rules. Our relationship with our horse is the greatest insurance of our safety. Intimidation works only as long as our intimidation is greater than the horse’s fear of other things.

Communication is much different in a driving situation than in a riding situation. We have only two ways to communicate – our voice and our line contact. We give up our body contact with the horse when we drive. There are no leg aids and no weight shifts. Instead we need to use our voice effectively with volume, speed, tone, rhythm and inflection to communicate our desires. Doc also recommends the use of a “stick” or wand to reassure and caress the horse. We also need to learn effective communication through the lines, and Doc teaches a rhythm method of driving using pressure release alternating left and right. A mechanical “team” was on hand for the students to practice this technique before they moved on to a real team. They also took turns driving each other around so each could feel not only what the driver feels, but the communication – or lack of it – that is transmitted through the lines.

It was not until the afternoon that the student’s horses added to the teaching. One mule came into the arena, brayed and pawed, digging a hole in the sand. When her owner corrected her, she replaced the pawing behavior with a yawing movement of her lower jaw until she could return to digging a ditch in the sand. The owner took her for a walk, but once she returned to be tied, the mule returned to her displaced behavior. Tom Triplet came over and commented on the excellent quality of the bray in the mule and laid his hand on her. He rubbed and stroked her roached neck and withers. Within moments the molly sighed, cocked her rear leg, lowered her head and relaxed.

Proper harness fitting was next on the agenda. Correct collar fitting was described and demonstrated. The ratios of hames to collar length, the proper positioning of snaps and pole straps, sweeneys and the problems of collars that are too long or too short were all discussed. Each horse that had harness was harnessed and the harness adjusted to fit. Each one had a place or an adjustment where the students could learn from the many examples.

Should we use blinders or not? “Let the horse decide.” Doc advised. “All horses should be desensitized enough to allow for not having blinders.” He recommends training both ways and then make an educated choice.

Several carts and wagons were on hand. Aspects of tongue and shaft weight were discussed and analyzed. Pointers were given on the things to look for in a vehicle and the things to avoid.

All parts of the clinic were hands on for the participants. Steady, well-trained teams were present so students could experience actually driving a horse or team if their horse was not yet ready to drive on a vehicle.

Build a foundation! We now have the tools, the techniques and the time to build our relationship with our horses correctly. When you get a horse, trained or not, start from scratch and build. This is your relationship with this particular animal. It is never too late for a new beginning.

Doc Hammill

As the needs, problems and interests developed, one on one instruction began, some with Doc and some with the capable co-instructors he had on hand to assist. Theresa Burns gave several students their first experience in driving and Steve Wood’s easy and straightforward help put both new and experienced students at ease. Groups and singles spurred off into different areas of the facilities to work on what they needed or wanted to learn. Some of the student horses had their first drive by the end of the clinic; some just got introduced to the concept while their owners gained knowledge to continue on after the clinic. Each time, the horse decided the pace of the lesson.

Doc Hammill was born in Iowa in 1944. He was born with a passion for driving and was always more excited by the idea of driving than riding. When his parents still lived in town, Doc remembers getting up early only on the mornings when a pair of older ladies and their horse and buggy would make morning deliveries of produce to the house. Later when the family moved to a small acreage, a young Doc Hammill would watch for hours as an elderly Slavic neighbor worked his market gardens with a single old gray horse and machinery. At the end of each row, the neighbor would stop, take off his hat and mop his brow and chat a while. The rhythm of the work, the steady pace, the cadence of the machinery, was all hypnotic.

Doc’s first attempts to drive were with a goat and a little red wagon. He fashioned his own harness and rigged it so when the goat would move forward the handle of the wagon would rise. His second vehicle was an old buggy that sat in the yard. With a set of pretend lines and plenty of imagination, the buggy bounced along for millions of miles. So many, that the wheels fell off and the buggy continued its journeys sitting on its axles on the ground.

Doc’s family were not horse people and they did not have a family history using horses, but one year as a present, Doc received a Welsh pony, a saddle and a bridle. He quickly talked some neighbors out of a flat bed garden cart, nailed pine 2 x 2’s to it as shafts and tied the 2 x 2s to the stirrups of the saddle. No one knows if the pony knew how to drive or not, but Doc jumped up on his wagon like Ben Hur and drove off.

Eventually, Doc also got to experience his first runaway and wreck. Remnants of the cart, shafts and saddle came rolling to a stop in the driveway. His saddle was replaced for his birthday with a new set of harness for the pony.  An old wagon was found and repaired and Doc and his brothers made many camping trips using the pony and wagon to haul their gear.

Early in his life, after a trip out west, Doc knew he would never be content in the Midwest. After graduating vet school, he and a friend traveled west, looking for opportunities. In a small town in Montana, they stopped to talk with the resident vet there. As it turned out, that very vet had been calling the school, looking for them, but no one knew how to contact the travelers. The Montana clinic needed another vet and Doc was the one lucky enough to be chosen for the job. It was about this time that Doc acquired his first draft horses, and has had drafts ever since.

Doc later opened his own vet clinic in Kalispell. A side business of horse marketing and consulting led him to helping manage breeding farms and ultimately riding the wave of the Arabian horse popularity. Like the tulips in 17th century Holland, the Arabian market showed signs of waning and Doc decided to leave that business and let his partner carry on while he developed another sideline business in an old west recreation town at a Montana ski resort.

Old West Adventures began as a recreation of a western boomtown with canvas covered buildings. Sleighs in the winter or wagons in the summer would bring up to 600 people at a time to a full blown old west dinner, replete with country musicians, historic talks, a barn dance and barbeques. Doc would also host three or four authentic wagon train trips through the Flat Head and Black Foot reservations each year. The wagons would travel around ten miles a day, everyone wore period clothing and only limited technology was allowed.

Old West Adventures sold in 1995 and because he had always promised himself a year off at some time in his life, Doc retreated into the Montana mountains as a caretaker to the ranch he now calls home. When he sold Old West Adventures, Doc took his brief case and his wristwatch with an alarm to the Good Will and melded into the mountains.

Doc realized he would have to generate an income again at some point and started giving old west historic talks for Elderhostels on Indians of the northwest plains, cowboys and cattle drives, horses and mules of the west and legendary horse whisperers. From there, his life experiences started to merge and he began offering five-day workshops at his ranch.

During all these years, Doc learned from many mentors. Among the teamsters he remembers best were “Addy” Funk, Tom Triplett, Glen Phanco, and George Moore. The northwest part of Montana was “frozen” in time then and still inhabited by people that had lived their lives with horses. He feels it was unusual and fateful to have known so many old timers that were as detailed and dedicated to their craft and took horsemanship to a higher level.

Dr. Robert Miller gets credit for opening Doc Hammill’s eyes to a gentler horsemanship when he gave a speech and demonstration in the 1970’s at a state vet’s meeting. Doc returned home from that meeting determined to convert and practice this new methodology. He studied the horse masters of the turn of the 20th century and the new horse masters of the turn of the 21st century. In his vet practice, he had plenty of horses and situations to practice his new skills. Over time, with trial and error and constant study on many horses, the process unfolded.

Driving and draft animals have been left behind for some reason in the natural horsemanship movement and Doc has dedicated his retirement life and skill to educating people to find a better way of communicating with their animals.

Today it is no longer a matter of life or death for most of us to depend on the working ability of our horses. A resurgence of horse farming as a hobby, hand in hand with natural horsemanship – or gentle horsemanship – has given us more consideration for the horse’s emotional and physical wellbeing. We have more time to look at the world from the horse’s viewpoint. We are beginning to realize that intelligent animals should not have to suffer needlessly to provide us with work or pleasure. Doc Hammill offers a gentler way of teaching the human and the horse to drive and to work together.

Originally published in Rural Heritage, Autumn ’07