Tawna Purcell DVM
Horses can get themselves into a variety of trouble causing an equally large variety of wounds. Not all wounds will require the same care. They can range from superficial scrapes to complicated lacerations. Regardless of the severity of the wound, the first thing to do is to thoroughly evaluate it and the horse to determine if prompt veterinary attention is required. Wounds near joints, the eye, down to bone, involving tendons, possible foreign bodies, severe lameness or bleeding, etc. should be evaluated immediately by a veterinarian.
The approach to wound care will vary based on the type of wound at hand; whether it needs sutures, drain placement, debridement, extensive cleaning, casting or joint lavage. We have many helpful tools to help us accomplish the best outcome of wound treatment. Based on the patient, the location and the character of the wound we can choose from 3 general categories of wound closure.
Primary Wound Closure: If a wound is fresh, clean and in a good location suturing will often lead to good healing with a desirable cosmetic outcome. However we often find wounds more than a few hours old and often contaminated with dirt and grime. This is where we can employ delayed primary closure.
Delayed Primary Closure: If a wound is contaminated, we can utilize materials to decrease swelling and clean the wound a few days prior to suturing and/or casting. A common dressing combination would be a hypertonic saline dressing (used to decontaminate and debride) underneath a cotton combine pressure wrap to decrease swelling. The bandage is changed every 24-48 hours until contamination is under control to allow suturing or casting. An example of a common wound would be a heel bulb laceration.
Second Intention Healing: Used in wounds that are not amenable to suturing, or where suturing has failed. Although this technique has a wide variety of modalities to be used based on the wound, a commonly involved concept is moist wound healing. When kept in a moist environment re-epithelialization (skin growth) occurs much faster than wounds exposed to air, as well as being less itchy, less inflamed, lower pain, shortened wound healing time and with less scarring.
In combination with certain bandage materials, the natural exudate of the wound can provide the best environment for healing, however there are instances such as burns and dry wounds that need help in the form of a topical dressing (such as Hydragels). Anti-microbial gauze dressing (AMD) can be used as an antibacterial barrier that will also absorb exudate while stimulating tissue growth. If the wound is heavily exudative calcium alginate dressing can absorb up to 20 times its weight in exudate while stimulating tissue growth, decreased bandage changes and decreased pain.
Excessive granulation tissue (proud flesh) can occur during wound healing, especially in the lower limbs. This can be challenging to address at times and there are many remedies out there. Depending on the amount of tissue present, de-bulking in combination with topical steroids and hydrophilic foam dressing under a pressure wrap is an excellent way to go. The hydrophilic foam dressing (COPA pad) does not allow granulation tissue to penetrate it, limiting its growth while also providing an excellent environment for normal healing.
When it comes to intestinal parasites (worms), each horse is different, each farm is different, and each paddock or pasture situation is different. So is it smart to deworm all horses the same? Probably not. While deworming too infrequently can cause real health problems in your horse, deworming too often can encourage the development of drug resistant parasite populations.
Measuring the actual number of eggs per gram of feces (EPG) using the McMaster’s Technique can quantify the worm burden of your horse. 300 EPG is the cut-off between high and low burden categories. Samples paired before deworming and two weeks after can give further information on the degree of anthelmintic resistance and the effectiveness of your deworming program. With this data it’s relatively simple to create a customized de-worming strategy for your horse.
This is an easy and inexpensive way to improve management of your horse’s health and potentially decrease parasite problems or dewormer cost.
As a horse owner, you play an important role in controlling your equine companion’s weight. Sound nutrition management, a regular exercise program and veterinary care are key to keeping your horse fit and healthy. Maintaining the ideal weight is not always easy, however.
When implementing a weight loss program for the overweight horse, it’s important to do it gradually and under the supervision of an equine veterinarian. Follow these guidelines from the American Association of Equine Practitioners (AAEP) to get you started:
1. Be patient. Weight reduction should be a slow, steady process so not to stress the horse or create metabolic upsets.
2. Make changes in both the type and amount of feed gradually. Reduce rations by no more than 10% over a 7- to 10-day period.
3. Track your horse’s progress by using a weight tape. When the horse’s weight plateaus, gradually cut back its ration again.
4. Step up the horse’s exercise regimen. Gradually build time and intensity as the horse’s fitness improves.
5. Provide plenty of clean, fresh water so the horse’s digestive and other systems function as efficiently as possible and rid the body of metabolic and other wastes.
6. Select feeds that provide plenty of high quality fiber but are low in total energy. Measure feeds by weight rather than by volume to determine appropriate rations.
7. Select feeds that are lower in fat since fat is an energy-dense nutrient source.
8. Switch or reduce the amount of alfalfa hay fed. Replace with a mature grass or oat hay to reduce caloric intake.
9. Feed separate from other horses so the overweight horse doesn’t have a chance to eat his portion and his neighbor’s too. In extreme cases of obesity, caloric intake may also need to be controlled by limiting pasture intake.
10. Balance the horse’s diet based on age and activity level. Make sure the horse’s vitamin, mineral and protein requirements continue to be met.
Once your horse has reached its ideal body condition, maintaining the proper weight is a gentle balancing act. You will probably need to readjust your horse’s ration to stabilize its weight. Exercise will continue to be a key component in keeping the horse fit. Because obesity can affect a horse’s health, communicate regularly with your veterinarian. Schedule regular check-ups, especially during the weight reduction process.
Rob Foss, DVM
An extension of the assisted reproduction program at EMS has reached a goal with the production of a pregnancy from the ovary of a deceased mare. In this instance a valuable older mare had to be euthanized in Kentucky but the owner still wanted another foal from her. After the mare was euthanized her ovaries were removed and flown to St. Louis and brought to EMS where six oocytes (eggs) were recovered. These were matured in an incubator and fertilized with ICSI (injection of a single sperm into the oocyte). Two of the six oocytes successfully formed embryos and a single pregnancy was established from those two embryos. The pregnant recipient mare was shipped to Kentucky where the owner is expecting a foal this coming summer.
Three-day-old embryos produced from a deceased mare’s ovaries.
Paul Schiltz, DVM
One of the primary complaints of the equine athlete is hock lameness. We see it commonly in nearly all performance horse types, from pleasure horses to gaited horses, from reigning horses to jumpers. Luckily most hock lameness can be effectively treated and managed to allow performance careers to continue. But what is it about hocks that make them prone to problems?
The hock of the horse is analogous in bone structure to the ankle, heel, and the back part of the human foot. It has 5 joints, most of which do not really move or perform any useful function. The upper joint, the tarsocrural joint, performs virtually all of the flexion and extension of the hock, and rarely has any problems. The lower 3 joints, the proximal intertarsal, distal intertarsal, and tarso-metatarsal joints, have no flexion or extension, but merely glide over each other in motions that are almost imperceptible. These motions, due to the great force an athlete can place on the limb, predispose these joints to rotation and compression injuries that can cause inflammation and soreness. In the early stages, this inflammation is known as synovitis, or inflammation of the joint membrane. Over time, synovitis results in cartilage loss and ultimately the development of osteoarthritis.
Although a single traumatic event such as a sprain or strain can produce distal hock pain, most cases are more of a repetitive use injury that occurs over years of work. Because of this, symptoms often develop slowly with a gradual loss of form over time. Common complaints include the horse not cantering well or unwilling to canter on one lead or the other, reluctance to stop and turn, unwillingness to load into the box during timed events, increases in time for speed events, and comments by the farrier that the horse is becoming more difficult to shoe. Unfortunately, because the pain tends to occur in both hocks, no overt lameness is detected early in the disease. Even when specific left or right hind limb lameness is detected with hock pain, there is a very good chance the “sound” leg is affected as well.
While the design of the hock and the work of the horse predispose it to hock pain we are fortunate that most hock lamenesses can be managed successfully. Treatment of distal hock pain depends on many factors such as the horse’s age and type of work. Most initial treatment involves injection of the affected joint(s) with medication to decrease inflammation and help return the joint to normal function. If the inflammation is minimal and cartilage damage has not occurred, only one injection may be required. In most horses, by the time the horse has developed symptoms osteoarthritis has occurred and intermittent injection may be needed to maintain the current level of athletic activity.
Filed under: Bacterial Disease, CEM, Reproduction, Stallion
Tawna Purcell, DVM
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Contagious Equine Metritis (CEM) has been a recent topic of concern for many veterinarians and some owners as of late. CEM, caused by the bacteria Taylorella equigenitalis, was first discovered in England in 1977 and was first identified in the United States in 1978 (in Columbia, MO). The disease was eradicated at that time until it made a brief showing again in 2006 and once again in 2008. Efforts to eradicate the 2008 outbreak are still ongoing.
CEM is highly contagious. Horses are often asymptomatic (no outward sign of infection) although some affected mares can show a mucoid vaginal discharge.
Transmission can occur through direct breeding, artificial insemination of a mare from an infected stallion or contact with items contaminated with the bacteria. Infection results in infertility or abortion in mares, while stallions have no clinical signs. Infertility can last for one or more breeding cycles and certain mares can carry the infection, potentially spreading it to others for many months.
Since the 2008 outbreak was first identified in Kentucky, a number of stallions and a few mares have tested positive for CEM, however some 991 horses, spread over 48 states, have been identified as potentially exposed to the bacteria that causes CEM. Most of these horses have now been tested as negative and the few found positive have undergone, or are in the process of treatment.
Testing of CEM is done in partnership between local and state veterinarians to insure proper methods and future eradication. There are three diagnostic methods available, the most common being bacterial culture in both stallions and mares. Should a mare test positive for the bacteria, a blood test will be done to detect systemic antibodies. Stallions do not develop these antibodies. Stallions who have tested positive, or who have been on a farm with a positive stallion will often undergo a test breeding to negative mares to insure he does not infect them with the bacteria. The process takes 35 days to declare the stallion negative. On average the process to clear a horse takes 6-8 weeks between tests and re-tests.
Although it may seem cumbersome, both mares and stallions can be diagnosed and successfully treated with topical and systemic antibiotics. That along with good hygiene practices will help eradicate CEM from the US once again.
Filed under: Corneal ulcer, Emergency, Eye Problems, Laceration, Uveitis
Hunter Ortis, DVM
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The most frequent eye related problems in horses are corneal ulcers (abrasions to the surface of the eye), eyelid lacerations and uveitis. Clinical signs of an eye emergency include excessive tearing or discharge, spasmodic squinting, holding the eye partially or completely closed, or constriction of the pupil. Additionally, changes in appearance of the eye and its surrounding structures such as swelling of the eyelids, increased redness of the usually pink tissue around the eye, and cloudiness of the cornea are signs of an eye problem.
The most common injury of the eye is a corneal ulcer. Ulcers occur when the surface of the eye comes in contact with a foreign object such a hay stem, stick or surface of a stall wall, leaving a defect in the integrity of the surface of the eye. A horse with a corneal ulcer will usually have symptoms of a painful eye and/or a hazy bluish appearance of the surface of the eye. Corneal ulcers are diagnosed with a fluorescing stain applied directly to the cornea during examination. Treatment usually includes topical antibiotics because the cornea is easily infected. Other medications may be indicated on a case by case basis.
Eyelid lacerations are commonly caused when the eyelid simply gets snagged on a piece of stall hardware, an overlooked raised nail or piece of wire. These injuries are much easier to diagnose than most other eye emergencies but are equally important to seek rapid veterinary attention. Most lacerations involving the margin of the eyelid will require repair with suture. The integrity of the eyelid margins is vital for maintaining a proper tear film on the surface of the eye. An irregular eyelid margin can cause recurring and chronic eye irritation.
Uveitis, or inflammation in the interior portion of the eye, occurs when inflammatory mediators are released causing leakage of damaging proteins into the internal structures of the eye. There are many different causes of uveitis including blunt or penetrating trauma, corneal ulcers, systemic diseases, and unknown causes to name a few. Most horses with uveitis will show signs of a painful eye that appears cloudy. Diagnosis is usually made with findings from a complete eye examination including the use of an ophthalmoscope. Rapid and aggressive treatment, often with multiple topical and systemic medications, is essential in minimizing the possibility of permanent damage to the internal structures of the eye.
Injuries of the equine eye should be considered an emergency, and owners should consult their veterinarian immediately when a potential problem has been identified. Delaying treatment or instituting improper treatment on some ocular conditions can lead to permanent damage to the eye and loss of vision.
Filed under: Cellulitis, Emergency, Joint, Laceration, Lameness
Nathan Voris, DVM
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Anyone with a horse has likely walked out to find them with a swollen, painful leg. While there are countless reasons for a horse to become “stoved-up” or “stocked-up”, one of the most common is cellulitis.
Cellulitis can be literally defined as inflammation of subcutaneous tissues. Many times, a cause for the swelling cannot be found, but some common reasons for cellulitis include “scratches” (pastern dermatitis), blunt trauma, lacerations or small puncture wounds. Inflammation, with or without bacterial infection, that is trapped under the skin, is clinically expressed as heat and swelling of the affected tissues thus resulting in a swollen, painful leg. Many times the horse will be severely lame and might even have a fever.
Treatment of cellulitis often includes hydrotherapy, sweat/pressure bandaging, anti-inflammatories and antibiotics. Efforts should be made to find the inciting injury as other diagnostic tests or treatments might be required to adequately treat the horse’s condition and to check the integrity of underlying bone and soft tissues.
Printed copies of the 2009 Equine Medical Services newsletter have been mailed. If you didn’t receive a copy, or if you would like a digital copy to share with friends, the on-line version can be found at the following link:
If you would like a printed copy mailed to you, please let us know and we will add you to our list.
Dr.’s Rob Foss, Paul Schiltz, Nathan Voris and Tawna Purcell attended the American Association of Equine Practitioners Annual Convention, the world’s premier continuing education meeting for equine veterinarians. The convention, held in Las Vegas, NV, December 5-9, offered veterinarians the latest advances in equine health care. Scientific sessions covering topics ranging from critical care to lameness were attended by an international gathering of over 2,500 veterinary professionals. Many of the sessions focused on providing new equine health care techniques that can be applied immediately to a veterinarian’s daily practice.
The American Association of Equine Practitioners, headquartered in Lexington, KY, was founded in 1954 as a non-profit organization dedicated to the health and welfare of the horse. Currently, the AAEP reaches more than 5 million horse owners through its nearly 10,000 members worldwide and is actively involved in ethics issues, practice management, research and continuing education in the equine veterinary profession and horse industry.