Stringhalt Stringhalt What is stringhalt? Stringhalt or springhalt is an involuntary, greater-than-normal flexion of the hock while the horse is in motion and may affect one or both hind limbs. How is this caused? The true cause is unknown, but the condition is associated with nervous disorders, degeneration of the sciatic and peroneal nerves which supply the muscles of this area, and affectations of the spinal cord. At any rate, the condition is considered to involve some pathology of the lateral digital extensor muscle. How does stringhalt affect the horse? The effects are quite variable, but the disease is easy to diagnose from the signs. Because the syndrome is erratic, it is often not obvious during examination. Stringhalt is apparently not painful and does not cause lameness in the usual sense. Some horses show a very mild hyperflexion of the hock during walking, while others jerk the leg up so violently that it strikes the abdomen and then pounds to the ground. Some horses show signs at each step, others only occasionally. In nearly all cases the signs are exaggerated when the horse is turning or backing. It usually is most noticeable after the horse has rested.

The flexion may increase in cold weather and decrease or even disappear in warm weather. This syndrome is not characteristic of any particular breed or breeds of horses. Does stringhalt prevent the horse from being usable? Although regarded as a gross unsoundness, stringhalt may not materially hinder the horse's capacity for work, except in severe cases where the constant concussion gives rise to complications. The judgment of a veterinarian will be valuable in deciding whether or not a horse may continue to compete in horse show performance classes. The veterinarian may or may not consider treatment of the syndrome necessary. What is the treatment for stringhalt? It is a surgical procedure to cut the tendon of the lateral digital extensor muscle. This may alleviate the condition and involves removing a section of the tendon and sometimes part of the muscle. The prognosis after surgery is guarded to favourable. Stringhalt in Horses | TheHorse.com Stringhalt in Horses Newsletters For centuries this neurologic disease has left veterinarians and scientists ­scratching their heads. A jerk, a jump, a hop with the hind legs tucked up high. Similar to the function of strings on a marionette, stringhalt seems to make horses yank their legs up and halt them there momentarily before taking their next step.

This uncontrollable exaggerated movement of the digital extensor muscles is the outward sign of neurologic disease, sometimes caused by toxicity, sometimes of unknown origin. If time doesn't cure it, the prognosis is poor. But today researchers are hard at work looking into ways to make horses with this condition safe, happy, and free of clinical signs. History, Clinical Signs, and Causes Stringhalt appears to be an age-old disease in horses and other hooved animals. Descriptions of the disease date back to the Renaissance. William Shakespeare has even been credited for the name of the disease (as a variation of the term "springhalt," from Henry VIII). Stringhalt occurs when the digital extensor muscles contract excessively or when the digital flexor muscles lack sufficient opposition, according to Caroline Hahn, DVM, PhD, MRCVS, Dipl. ECEIM, ECVN, senior lecturer and researcher in the neuromuscular disease laboratory of the University of Edinburgh's Royal (Dick) School of Veterinary Studies, in Scotland. The clinical signs are usually more extreme when the horse is turning or backing up. Some horses have such severe stringhalt they actually kick themselves in the abdomen when trying to walk.

Both hind legs might be equally affected, or one might show more obvious signs than the other. In some cases stringhalt might be apparent in the forelegs. Clinical signs, such as pastern extension when the hock is flexed, can vary from one horse to another, Hahn says. Shivering is another sign of the disease, she adds. Although stringhalt might look like strictly a muscular problem, neurologic issues are at the root of it. Nerve damage probably causes abnormal activity of certain sensory receptors called spindles, says Hahn. Located in the body of the muscles, spindles are responsible for detecting changes in muscle length. This faulty wiring of the spindles causes certain muscles to contract either too early or too late, or too much or too little, during certain phases of the gait. "Thus, intermittent abduction (movement of the limb away from the body) and caudal (toward the tail) jerking in the hind limb may result from spasticity of the biceps femoris muscle (located along the back of the hindquarter) during the swing phase of the stride," she says. Veterinarians divide stringhalt into two major categories.

"Australian" stringhalt usually is a temporary disease resulting from toxicity, whereas "classic" (or atypical, depending on the geographic region) stringhalt has no known cause and usually does not resolve on its own. Australian Stringhalt Stringhalt in outbreaks caused by the ingestion of toxic plants has acquired the common name of Australian stringhalt. It was originally described by veterinarians in Victoria in the late 19th century. However, despite its name, Australian stringhalt can affect horses worldwide and has commonly been reported in the United States and New Zealand, in addition to Australia. Recently, it also has been diagnosed in some South American countries. Over the past century, false dandelion (Hypochaeris radicata), also known as flatweed, has been considered a major culprit of Australian stringhalt, according to José Allan Soares de Araujo, DVM, PhD, researcher at the veterinary hospital at the Universidade Federal de Campina Grande in Patos, Brazil, and author of a recent study describing two outbreaks of Australian stringhalt on Brazilian Thoroughbred farms. New cases appear most often in late summer or fall, frequently in horses grazing on poor-quality pastures where weeds are abundant.

Australian stringhalt affects the peripheral nervous system (outside the central nervous system, which includes the brain and spinal cord), almost always affecting both hind legs more or less equivalently and sometimes the forelegs, says Hahn. Horses should be removed from their pasture as soon as clinical signs appear, says Nicholas Kannegieter, PhD, BVSc, DVCS, FACVs, specialist equine clinician based in the Roseville Equine Clinic in New South Wales, Australia. Away from the toxins, the median recovery period for most horses is six to nine months, although for some it takes a few weeks and for others a few years. Horses with signs of stringhalt in their forelegs take the longest to recover. The horse's largest nerve fibers are the primary targets of Australian stringhalt; these are in the hind leg and the larynx (voice box), which are both usually affected by the disease, Kannegieter says. The hindquarters show the most obvious clinical signs, but some horses also will emit a hoarse "roar" when they whinny. Even when the gait returns to normal, the laryngeal nerves of some Australian stringhalt-affected horses are damaged.

Unfortunately, this can leave them with permanent deficiencies in athletic performance (due to airway restriction), he says. Other plants, including the common dandelion (Taraxacum officinale) and cheeseweed or little mallow (Malva parviflora), also have been linked to Australian stringhalt, but flatweed remains the common indicator plant. Araujo found that false dandelion was the certain cause of the two Brazilian outbreaks he described. His research group was able to provoke Australian stringhalt in a young horse by feeding him false dandelions picked from a field where an outbreak had occurred. The horse developed clinical signs within three weeks and showed improvement within days of the researchers removing the plants from the diet, Araujo says. (The horse fully recovered 15 days after the experiment ended.) However, not all false dandelion or other suspect weeds cause stringhalt, and many horses graze in affected paddocks without issue. Toxicity of the same species of plant can vary from one location to another, according to Araujo. Environment might play a role in providing optimum conditions for producing the toxin, says Kannegieter.

Classic Stringhalt Unlike Australian stringhalt, classic stringhalt does not typically occur in outbreaks and usually has no obvious cause. Clinical signs are similar, although classic stringhalt frequently has stronger effects in a single leg. Injury to the back, neck, or leg could be the underlying source of the condition. In these cases the stringhalt might improve once the injury heals, Hahn says. When no injury is obvious, however, the reason a horse develops stringhalt is difficult to determine and might never be known. Arthrosis (degenerative joint disease) and perhaps osteochondritis dissecans (OCD, a cartilage disorder characterized by large flaps of cartilage or loose cartilaginous bodies within a joint) at the joints, primarily in the neck, could be the cause, according to Inge Wijnberg, PhD, DVM, an assistant professor in equine internal medicine at Utrecht University, in the Netherlands. There she focuses on neuromuscular disease in her research. "We see a lot of young horses in our referral clinic with issues in the C5 to T1 area (certain neck vertebrae)," she says.

"Some horses do have problems in the peripheral nerves, but the vast majority of cases in our clinic have lesions in the cervical or upper thoracic (chest) area as opposed to the lumbar (loin) area. These lead to upper motor neuron (connecting the brain stem to spinal cord) abnormalities which seem to be related to the stringhalt." Frequently the clinical signs progress in these horses, and more intensive work or training might actually make them worse, Wijnberg says. "A lot of times owners will say they noticed something a little funny around age three, but then it gets much worse by the time the horse is five. That's often the age that dressage horses start a lot of the more complex gymnastics activities. So the stringhalt might advance because of age, or training, or both. We don't know yet." Genetic links are questionable, she says. "But even if there might be some correlation, OCD has so many causative factors that it's difficult to pinpoint genetics." Diagnosis and Treatment Horses with stringhalt symptoms should be evaluated by an equine veterinarian with experience in neuromuscular dysfunction, Wijnberg says.

However, horses with Australian stringhalt do not require the same extensive diagnostic procedures as those with classic stringhalt, because the cause is more apparent. Hahn recommends a thorough orthopedic exam, including radiographs (X rays) and ultrasound of the affected leg, to look for potential problems in the lateral (closer to the outside than the midline) digital extensor muscle, tendon, or hock. "Any abnormalities detected often are assumed to initiate abnormal nervous system reflexes, increasing tone in the digital extensor muscles during stride," she says. Vets should consider differential diagnoses such as muscle diseases, including polysaccharide storage myopathy, she adds. In Wijnberg's clinic, patients with stringhalt symptoms are hospitalized so they can be examined several days in a row, because gait diagnosis is often fairly subjective, she says. She relies on a combination of extensive clinical examinations, which include an orthopedic workup, diagnostic imaging, and electromyographs (EMGs, tests that measure electric signals in the muscles), for accurate diagnoses. "People can have a lot of differences of opinion about the severity or even existence of the disease in certain horses," says Wijnberg, who recently published a report on diagnosing stringhalt via EMG.

"The EMG gives us a clear reading of what's going on in the muscle and really takes out the 'I think' part of the diagnosis." Clinicians must use specific descriptions of the kinds of clinical signs being displayed to reach clear diagnoses, she says. "We try to stay away from fast slang, like 'stringhalt,' when we initially examine a horse," she says. "Is it hypertonia (increased rigidity, tension, and spasticity of the muscles)? Hypermetria (an ataxic muscle disorder characterized by overreaching)? Lateral or parallel? Neurological problems are complicated, so it's important to describe what you see first and foremost." Muscle relaxants, anticonvulsants, and drugs that work directly on the central nervous system can be helpful for some horses with long-lasting stringhalt, according to Kannegieter. Unfortunately, these medications might also act as sedatives, and their effects are often temporary, Wijnberg says. Long-term medical treatment is also expensive and risky in competitive situations, as it could result in positive doping tests. Surgical resection of a part of the tendon running along the hock is another option, but its success rate varies.

Many horses do not recover from stringhalt despite these treatments, she says. New Research Like many other neurologic diseases, stringhalt is the subject of active, ongoing research. Scientists are seeking new causes as well as treatments, Wijnberg says. Her research unit is collaborating with the University of Bern to deepen their understanding of the origin of stringhalt based on post-mortem examinations. However, lack of cadavers is hindering this research. The botulinum toxin Botox, commonly used to smooth facial wrinkles in humans, is under investigation at the moment for its use in calming stringhalt symptoms, Wijnberg says. Her recently published results on the subject were promising, showing reduced clinical signs in the affected test horses, and noting Botox might be even more effective in higher doses. Thus, Wijnberg is now developing new "retraining" protocols, she says. "If it's an upper motor problem based on a vertebral lesion with lots of arthrosis, I can't fix that," she says.

"But I can try to retrain the horse to get around the problem." The goal, she says, is to use Botox temporarily to "get the horse out of his loop" until he has learned to overcome the neurologic issues. It isn't as far-fetched an idea as it might seem: Similar goals are currently being met for people with upper motor neuron disorders. With a bit of luck, and a lot of skill and patience, equine neurologists might soon know just what it takes to cut the strings of stringhalt horses forever. About the Author • Horses: 0 Hi, Unfortunately, by what you've said, it sounds like the knock on the head may be as possible a cause as stringhalt. I'd want to get that checked out too. Stringhalt is also a nervous/neurological disorder. If 'abnormality of gait' is the only thing, depending on what that means, it could also just be that she put her back out or such kicking at the new addition. Horses with stringhalt typically have difficulties backing up & in more extreme cases may actually kick or scrape their belly with every step of their hind legs.

It doesn't tend to affect front legs until well advanced, and if left can also lead to blindness. Given that she's in a new field, I'd be inclined to get her out of it immediately, back to a definitely safe one until you've ruled out possibility of stringhalt. It is thought to be a severe lack of magnesium, so not necessarily a specific plant that causes it, but often capeweed or other flat weed seems to be a big culprit - perhaps these plants are an indication of the lack of mag. It seems to be a cumulative thing - the more they eat of it the more they're likely to develop problems. Some also seem more susceptible than others, and I've known of cases where only one or 2 in a herd get it & all others are fine. Paddocks dressed with dolomite or such, and horses fed well balanced supps don't tend to be susceptible to the problem. I've known horses who were rehabilitated & completely over it, but think it depends on how severe, how long they've been so magnesium deficient & allowed to graze problem pasture as to the prognosis. My 'Natural Horse Care' book by Pat Coleby says... Remove the horse from the offending paddock.

No lucerne hay or grain. Feed 2 tablespoons of dolomite daily, add one dessertspoonful of epsom salts for 10 days only; also 3000mg magnesium orotate twice a day from the start. Immediately the horse starts to improve, cut the magnesium orotate to half. Once the animal is fully recovered, delete the magnesium orotate and restore the dolomite to the normal dose. loosie is offline Burlington Equine Veterinary Services, LLC Under Saddle Core Strengthening Exercises for Horses Neuromuscular Diseases In this article I will explore the interrelationships between three disease processes: Equine Polysaccharide Storage Myopathy (EPSM), Stringhalt and Shivers. These three syndromes have been seen more frequently over the past 10 years. Shivers may be a new disease for some of you, but it has been present in Draft horses for quite some time. The Drafts still have issues with this, but its presence in Warmbloods is our greater concern. The gait abnormalities associated with this disease are particularly problematic for dressage horses, but even such routine procedures as farriery and the daily picking out of hooves can be affected by it.

EPSM EPSM is a metabolic condition related to skeletal muscle dysfunction. The primary issue is an inability to properly metabolize carbohydrates from feed. Attempting to make dietary changes and maintaining a schedule of regular exercise seems to be the most effective methods to improve these horses. This is a lifelong condition and altering the carbohydrate to fat ratio will be a permanent change. Potentially any type of horse could develop this condition, with the highest incidence involving Warmbloods, Draft-related breeds, Quarter Horses and Arabians. It is thought to be an inherited disorder, but due to variability in its onset this may not seem clear. There are a variety of signs reported thus making it difficult to conclusively diagnose this based on history and signalment. Clients have reported: an onset of weakness, poor performance, an inability to move forward, back soreness, gait abnormalities with or without a lameness, attitude problems, poor muscling, decreased impulsion and general stiffness. From this list we could probably come up with 30 or more reasons for these signs. What also makes this difficult is that a horse can be progressing normally in a training program then some of these signs can develop subtly.

Over time the gait abnormality when recognized may not be clearly linked to any particular change in the horse's diet, work or routine. An actual lameness may develop from a slight stiffness to an actual lameness that involve one or both hind limbs. From behind the gait has been described as a "goose waddle". One of the more obvious horses I saw was a 4 year old Draft gelding that walked out of the stall stiffly and would trot, but appeared stiff and lame in both hind limbs. There was not muscle loss, but they were not developing well and they seemed remarkably tight and sore for the limited work the horse was doing. The lameness and sometimes vague signs make it difficult to distinguish EPSM from other causes of lameness, including Shivers and Stringhalt plus different neurologic conditions. Attempting to diagnose EPSM with laboratory work is a worthwhile pursuit, but it still may elude an accurate diagnosis. The primary blood test involves looking at levels of muscle enzymes before and after exercise. Muscle enzymes will increase with exercise and the higher the rise the more likely that muscle inflammation is occurring. Unfortunately not every horse will exhibit the type of elevation necessary to diagnose this from bloodwork.

A second method is by doing a muscle biopsy, which allows a pathologist to make the diagnosis based on a microscopic examination of the muscle tissue. The procedure is straightforward and well tolerated by the horse. Since this is somewhat of an invasive procedure most clients opt to treat rather than to biopsy. In order to confirm the diagnosis and to get a sense of the degree that EPSM is involved in the unsoundness, biopsying is essential. A new genetic test has become available that evaluates DNA from hair or blood to determine if the horse carries the gene for what is being called Type 1 EPSM. The Type 2 - the more common form is only diagnosed presently through a muscle biopsy. This horse demonstrates a more extreme example of stringhalt. Typically the involuntary snapping up of the hindleg may not involve the whole body as it does in this case. Stringhalt This gait abnormality shares some of the signs seen with EPSM, yet there are a few things that make it unique. Potentially any breed can be affected by this condition and there is no age or sex predilection. The classic sign is described as an exaggerated flexion of the hindlimb that occurs during the walk stride.

The flexion can be quite dramatic as the front of the fetlock can actually contact the horses abdomen. Once the horse continues moving and gets into trot and canter gaits the signs may dissipate altogether. It can be seen in one or both limbs. Horses with both legs involved generally have one leg more obviously affected than the other. In addition most horses with this syndrome seem to be affected more during the cold weather and stress. It may show up in the walk or when you first pick up a hindlimb and most horses improve even after a few minutes of walking. The condition is frequently noticed when picking out the feet and when the farrier works with the horse. While starting to back a horse an abnormal flexion may be shown which could be consistent with either Stringhalt or Shivers. There are several potential causes and some type of neuropathy - a nerve dysfunction is the most common. There are times when this neuropathy develops for no apparent reason and other times a traumatic event may be linked. I know of several horses where this developed after trauma to the area above and to the side of the hock as well as in the upper cannon bone region.

Some type of contusion may have resulted in a permanent change in the ability of a nerve to properly conduct impulses or for a tendon attached to a flexor muscle to function properly. In the Northwestern U.S., parts of Europe and Australia the disease has been linked to a toxic agent in a plant. If Stringhalt can be linked to plants then the goal is to remove the horse as soon as possible from that location. Unfortunately toxicity is not a cause in the New England area and our attempts to treat and manage this condition are limited. I will cover medical options at the end of this discussion. Draft horse exhibiting the classic stance for shivers. The leg may only go about this high before it starts to shake or quiver. Often this occurs when someone reaches down to touch the leg and asks for it to be held off the ground. Shivers Initially this condition was diagnosed exclusively in Draft breeds, but it has been seen with an increasing frequency in Warmbloods. Perhaps because of the similarities with respect to abnormal gaits, some of the horses previously diagnosed as being affected with Stringhalt may in fact be Shivers horses. In the Veterinary literature there have been reported cases in other breeds, however in our practice the Warmbloods have been affected the most.

There may be several signs associated with this syndrome. The classic abnormality is an exaggerated flexion of the hindlimb, where the limb may be held in the flexed position and quiver for 10-30 seconds. The shaking is different from Stringhalt which is a quicker more spastic type of movement. In addition to the quivering the leg may be held somewhat away from the body when it goes into flexion. The tail may be partially raised during one of these episodes. On occasion flickering of the eyelids and ears may occur along with a stretching or flexing motion of the neck. I frequently find they appear to be neurologically impaired yet when we do a neurologic exam with positional responses and reflexes these horses are normal. The signs may be evident in numerous situations: turning in a tight circle at a walk, starting to trot, walking backwards and when an attempt is made to pick up a hind foot. Some of these horses seem to have an inability to pick up the limb when asked and if they do "release the limb" and allow it to be held then the quivering will be seen and some of these horses may require using a wall to balance themselves on the opposing limb.

Initially the gait abnormality may consist of an unevenness in a hind limb that may progress to a "hitch". Over time this could progress to involve both hindlimbs with the flexion abnormalities as previously described. Since the horse may have functionally normal gaits beyond the walk the syndrome may be misdiagnosed as Stringhalt, EPSM or an intermittently locked stifle. A hitch in the stride could run the gamut for any cause for a hindlimb lameness. Determining a cause for this syndrome has taken researchers in several different directions with a neuropathy being considered likely. Attempts to prove that a neurologic component is present has yet to be determined. Instead affected horses share some of the same metabolic issues that affect those with EPSM. In my opinion due to the signs occasionally seen affecting the head and neck coupled with gait abnormalities, I am still not convinced there isn't an underlying neurologic process involved. Treatment Strategies As previously discussed diagnosing these conditions may be difficult and treatments can be just as confusing. Generally attempts to improve affected horses involve dietary manipulation since metabolic issues play an important role in EPSM and Shivers.

Only Stringhalt is amenable to a surgical procedure and success rate is generally in the 70% range. Since Stringhalt may not affect a horse's gait enough to warrant surgery most people elect to live with this condition. In the past, I have attempted using Vitamin E supplementation as a means of management, but at this point I am not convinced that this will offer many advantages. Dietary recommendations for the two metabolic diseases (EPSM and Shivers) are designed to move the horse away from a high carbohydrate diet and to provide approximately 20-25% of total daily calories from fat. Most horses are receiving a sweet feed or pelleted ration that contains high levels of carbohydrates. Although some of the newer feeds are increasing fat content up to 10-12% there has not been a significant change in the carbohydrate content. Some horses are supplemented with vegetable oils, ( corn, cocosoya or soy ) high fat feeds and supplements such as Rice Bran. Still in order to modify the dietary content of the feed there will need to be substantial increases in overall fat content beyond what most people routinely feed. Much of the work done investigating these conditions has been done by Dr. Beth Valentine and recommendations are based on her research.

A change in a horses diet to one that contains these high fat levels is safe and may be used as a "test" to evaluate if a horse is a candidate for these type of syndromes. It may take 1-2 weeks to make the necessary changes some of this depends on the horses current diet, body condition and acceptance of the addition of oil. For an average 1000 pound horse one simple diet is to replace grain with an equal quantity of alfalfa pellets and gradually add vegetable oil until the horse is eating 2 cups of oil per day. The alfalfa was suggested as an adequate source of protein, calcium and Vitamin E with good palatability. Alfalfa hay can also be added to the mixture. For horses that are not accepting of this diet feeding a high fat feed instead of the alfalfa pellets is an option: Purina Athlete, Purina Strategy, Blue Seal Demand or Blue Seal Hunter. If the oil is a factor the palatability can be improved by using Cocosoya oil, which is a blend of coconut and soy oil. The two oils that should not be used are linseed and flax seed.

Rice Bran which is 20% fat can be used to supplement or to replace some of the oil. The conversion of the rice bran to an equivalent amount of oil is as follows: 5 pounds of rice bran provides the same amount of fat as 2 cups or 1 pound of oil. Feeding with rice bran as the primary fat source will substantially increase costs and not reduce the carbohydrate or starch content as much as desired. Dried fat sources are also available and provide an alternative to the oil. These products weigh half of their volume so twice the volume will be required. You would start with at least 4 cups of dried fat per 1000 pounds of horse's weight. Combining dried fats, oils, rice bran and/or high fat feeds can be used to achieve similar results. The difficulty lies with the feeds that are reportedly high fat. The actual % of fat may be 10-12%, but what they do not report is the carbohydrate %. As more feeds are used in the feeding regime the potential for throwing off the carbohydrate to fat ratio exists. For example, a feed with 10% fat would require feeding up to 10 pounds in order to achieve 1 pound of fat from the feed.

Obviously this will be too much grain and by increasing this in order to help manage fat content you will undoubtedly significantly increase carbohydrate levels. Therefore the use of oils as a 100% fat source is the safest and most efficient means to get the desired results. The diets discussed here are designed for horses weighing approximately 1000 pounds which is about the weight of the average Thoroughbred or Quarter Horse. A Warmblood may weigh closer to 1200-1300 pounds and the feed should be increased accordingly. The minimum caloric requirements for a 900-1000 pound horse is 10,000-12,000 calories per day. As the horse's work regime increases so will its demand for calories. The high-fat oil-based diet provides 16,000 calories per day. One cup of oil contains 2,000 calories, and in this diet the 2 cups will provide 4,000 calories, which is 25% of the total calories. If a horse gains too much weight or is already heavy then it may be necessary to decrease grain and/or access to grass, plus increase the work schedule.

Feeding extra sources of vitamins and minerals is generally not a bad idea if a general supplement is needed. However I feel particular attention should be given to Vitamin E which should be fed at higher levels. Generally we suggest giving the horse at least 1 unit of Vitamin E for each pond of the horse's weight. In my opinion these horse do better with at least 2-5 times that amount. I recommend using E-5000 sold through Vita Flex that contains 5000 units per measure. If you are already feeding a Vitamin E-Selenium supplement we don't want to use this to increase Vitamin E as there is a risk of toxicity if Selenium is increased beyond the 1 mg per 1000 pounds of weight. If this type of oil-based diet is chosen it may be necessary to increase oil every few days by 1/4 increments to not throw off palatability. Results may take up to 4 months in order to realize full fat adaptation. Some horses have exhibited improvement in as little as 1 month with an improvement in gaits, attitude and energy. Over time improvement in the horse's musculature is to be expected.

Potential set backs have occurred and may be associated with variables such as access to grass or hay. There can be a significant increase in grass carbohydrate content especially in the spring and after the initial onset of cool weather in the fall as grasses will concentrate sugars. Paying particular attention to the pastures and hay, such as first versus second cut will help. see article on Feed Information References Valentine, BA Mechanical Lameness in the Hindlimb. In Lameness in the Horse Ross, MW and Dyson, SJ St. Louis, Mo. 2003 Valentine, BA Diagnosis and Treatment of Equine Polysaccharide Storage Myopathy Journal of Equine Veterinary Science 2005; 25:52-61. Content © 2017 Burlington Equine Veterinary Services, LLC 248 Plouffe Lane Examining the horse for nervous system diseases : University of Minnesota Extension Extension > Agriculture > Livestock > Horse > Horse health > Examining the horse for nervous system diseases Examining the horse for nervous system diseases Carrie Finno, DVM, PhD, University of Minnesota A healthy nervous system is essential for equine performance. However, when do you need a complete neurologic examination performed on your horse?

Your horse has begun tripping or having problems going up and down hills Your horse has subtle performance problems that are not a clear lameness but appear to shift from leg to leg. This “mystery lameness” is often difficult, if not impossible, to localize and treat. Your horse has undergone an abrupt behavior change Your horse often stands in an abnormal position Your horse has lost muscle mass You have a young horse that you have started working with and noticed some gait abnormalities You have a young foal that appears uncoordinated or has difficulty turning his neck Your horse developed a droopy ear or his muzzle is pulled to one side Your horse suddenly began to carry his head tilted and leans or often circles You are having a veterinary examination prior to purchase Your horse is dripping urine or having trouble passing manure If you or your veterinarian suspects that your horse has neurological disease, it is necessary to have a full neurologic examination performed. Neurologic disease can be difficult to sort out in the horse and it is important to have a veterinarian experienced in neurologic examinations examine your horse. Similar to physicians with specialization in neurology, there are board certified large animal internal medicine specialists at the University of Minnesota that specialize in neurologic disease.

We begin asking, first, does a neurological problem exist? Second, what and where in the neurological system is the problem located? A detailed examination can provide answers to these questions. What does a neurologic examination involve? Questions in a complete medical history often include: Age, sex and breed of horse. This is important as certain diseases are more common at a particular age or in a particular breed. Clinical signs. What have you noticed about your horse that you think is abnormal? When do these signs occur (at rest, when riding in the ring, only on trails, etc.)? Onset of clinical signs. Did you notice these signs suddenly or did they seem to develop over a long period of time? Progression of clinical signs. Have these signs worsened since you first noticed them or have they stayed the same? Did any treatments appear to improve them? Did you try resting your horse and, if so, did he improve? What type of riding do you do? How many days a week do you ride and for how long? Do you actively compete your horse? Has your horse's performance changed since you noticed the abnormalities? How long have you had your horse? Did you have a prepurchase examination performed prior to buying him?

What did the previous owner use your horse for? Have any other horses at your barn appeared abnormal too? If so, are they housed together? Are they related? Does your horse have difficulty laying down or getting up? Can he urinate and pass manure normally? What vaccines has your horse received most recently? How often do you booster them? What deworming protocol do you use and when was the last time your horse was dewormed? What does your horse eat and where does he live? It is often very useful if owners keep a journal of any changes noted in their horse's behavior or gait. Digital videos showing the abnormal behavior are great to have, especially if the horse only does the behavior under certain conditions. Sometimes, horses won't show the abnormality when the veterinarian is examining them, either because they are more stressed than usual or in an unusual environment, such as a referral vet hospital. It can be very frustrating to go through all the trouble of scheduling an appointment only to have your horse not show the strange behavior or abnormal gait so taking the time to make a video is worthwhile. The examination used by specialists in internal medicine is described below. Step 1: Examine in the stall/paddock.

We begin by assessing your horse in a stall or small paddock, wherever the horse is more comfortable. One of the first things to evaluate is your horse's mentation, which means is your horse behaving normally for the environment that he is in. If your horse is in a new environment, he should be bright and alert and looking around. If your horse is in their stall at home, he/she may be quieter, but still appear bright when someone enters the stall. Next, is looking to see how your horse moves around the area. Does he stumble or bump into things? We assess how your horse stands at rest, or his posture. Horses do not need to stand squarely at all times but they shouldn't rest with one or more limbs out from under their trunk for extended periods of time (Figure 1). Then the resting respiratory rate is taken while your horse is in the stall or paddock before being handled, which may excite him. During this time, your horse's body condition score, which is a score assigned based on your horse's weight (is he too skinny, in good condition, or too fat?) is recorded. Step 2: Full physical examination at rest.

After the initial observation, a routine physical examination is performed, which includes assessing your horse's cardiovascular, respiratory, gastrointestinal and musculoskeletal systems. Liver or kidney disease can have neurologic signs, and some abnormalities might be apparent on a general physical examination. It is always important to perform a basic lameness examination at the same time that the neurologic examination is performed because they are often difficult to distinguish. In addition, in many horses, there may be both a lameness and a neurologic component to the problem. While your horse is standing for his physical examination, we pay careful attention to his muscle symmetry to determine if there is any atrophy, or loss. Muscle atrophy may be symmetrical or asymmetrical and provides useful information (Figure 2). The hooves are examined for abnormal wear. Horses that drag their hind toes often square the toe off. A basic ophthalmologic examination may be useful if your horse is running into objects as he may have a primary eye problem. Step 3: Full neurologic examination: cranial nerves. The next thing to perform is an examination of your horse's cranial nerves. We begin by performing a menace response, where a hand is "menacingly" moved towards your horse's eye.

The correct response is to blink. This response is tested from both the inside (medial) and outside (lateral) approaches to fully evaluate this reflex. While examining the eyes, the pupillary light reflex is tested, where a bright light is shone in your horse's eye and the pupil constricts. While performing this test, pupil position is also evaluated. The pupil should be in the center of the horse's eye and should not be moving when the horse's head is held still. Next your horse's facial sensation is tested (does he have sensation up his nostril, along his eyelid and in his inner ear?) and muscle tone to the face (is there any evidence of facial asymmetry, such as a droopy ear or eyelid or a muzzle that deviates to one side?). We also assess muscle symmetry of the masseter (cheek) muscles and the temporalis muscles under forelock. Your horse is carefully evaluated for a head tilt and a temporary blind-fold might be used, where a towel is placed over the horse's eyes to see if this makes it worse. Lastly, your horse gets a treat for being such a good patient and in order to assess his ability to chew and swallow.

Your horse thinks this is the best part of the exam! Cervical (neck) region: A horse's neck is felt on both sides of its spine from its head to its withers for pain or swelling. Then flexibility of the neck is tested by offering treats on each side at the shoulder and determining how far the horse can stretch. It is important to remember that, although abnormalities in these tests might indicate neck pain, they are often very subjective. The cervicofacial reflex is tested by pushing a blunt object, such as a pen cap, into the skin on his neck and noticing if the horse twitches its ear or grimaces on the same side, which is a normal response. Thoracolumbar (trunk) region: The cutaneous trunci reflex, which is the skin rippling reflex that horses use to keep flies off, is tested by looking for a twitch response to pressure. Sacrocaudal (tail) region: A horse's tail and anal tone are examined to determine if there are any abnormalities that could be localized to the sacrocaudal region. If a horse has had difficulty urinating or passing manure, a rectal examination is used to further assess this region.

Gait exam: Assessing a horse's gait is an important part of the exam. The most common series of maneuvers include walking and trotting in a straight line, walking in serpentine figure, spiraling in on a circle at the walk, backing, going up and down an incline and on or off curbs or steps, walking with your horse's head elevated, and the tail pull. All of these tests are aimed at evaluating the gait and coordination when your horse is asked to do complex movements. When circling, it is important to pay careful attention to a horse's leg position. Does the horse make mistakes and step on himself? Does the horse drag its forelimbs when backing? Sometimes, in subtle cases, it is necessary to perform a full gait examination, then lunge the horse for 15 to 20 minutes, and repeat the gait examination. Subtle abnormalities that were not noticeable before exercise may become apparent after some work. Interpreting the neurologic exam: grading system: Once the exam is completed, a veterinarian will have an answer to the original two questions: (1) Does a horse have neurologic abnormalities?

(2) If the horse does, where do they localize to and how severe are they? To answer question #2, a veterinarian will localize a horse's clinical signs to either a region of the brain, spinal cord or to a peripheral nerve (i.e. nerve outside the spinal cord). If a horse demonstrates a spinal ataxia (i.e. in-coordination originating from the spinal cord), a grading scale to determine how severe a horse's gait deficits are is assigned. Each limb is graded separately with regard to four aspects: ataxia (incoordination), weakness, dysmetria (a combination of overshooting and weakness commonly observed with disease of the cerebellum) and spasticity. Grade 0: Normal; no deficits observed; Grade 1: Mild intermittent gait deficits; Grade 2: Mild consistent gait deficits; Grade 3: Moderate consistent gait deficits; Grade 4: Severe consistent gait deficits; or Grade 5: Recumbent. A great deal of experience is required to interpret the signs, localize them to the proper region, and to select the best diagnostic tests.

As we continue this series, we will discuss the four most commons causes of spinal ataxia , and the diagnostic tests that can be used to try and determine which of these diseases is responsible for a horse's clinical signs. The neurologic exam answers two questions: does your horse demonstrate neurologic abnormalities? If yes, what specific part of the nervous system is affected and to what severity? Localizing the clinical signs to specific regions within the nervous system is important because different diseases affect different regions. The following region/categories are often used: Cerebrum (part of the brain responsible for consciousness and thought processes) Cerebellum (part of the brain that allows for smooth movement patterns and control) Brainstem (part of the brain that controls heart rate, breathing, facial nerves and relays sensory and motor pathways from parts of the spinal cord) Spinal cord (cervical [neck], thoracic [withers and back], lumbosacral [hindquarters]) Peripheral nerves (part of the nervous system OUTSIDE the brain and spinal cord) Neuromuscular junction (where the peripheral nerves and muscles meet) Diseases that affect the spinal cord are the most common neurologic abnormalities encountered in the horse.

If your veterinarian suspects neurologic abnormalities that localize to other regions, the diagnostic tests would differ from what are discussed here. The predominant clinical sign involved in all the diseases we will be discussing is ataxia. Ataxia is defined as the inability to control voluntary movement, and most frequently results from disorders in particular regions of the brain or spinal cord. There are different types of ataxias: Cerebellar ataxia: irregular, uncoordinated movement that is due to dysfunction of the cerebellum Sensory ataxia: ataxia due to the loss of proprioception (joint position sensation) that results in poorly judged movements. Sensory ataxia is typically caused by abnormalities in the spinal cord, although portions of the brain may be involved as well. Vestibular ataxia: ataxia that may result in a head tilt, circling and imbalance due to abnormalities in the balance (vestibular) system within the inner ear and brainstem. Sensory ataxias due to spinal cord disease is common.

Many horses with sensory ataxia will also present with signs of weakness and a veterinarian will classify the type of weakness as upper (hyperactive, signs of spasticity) or lower motor neuron (diminished reflexes, muscle atrophy). Your horse's neurologic signs will be graded. Each limb is graded separately with regard to four aspects: ataxia, weakness, dysmetria (combination of overshooting and weakness commonly observed with disease of the cerebellum) and spasticity. Grade 0: Normal; no deficits Grade 1: Mild intermittent gait deficits Grade 2: Mild consistent gait deficits Grade 3: Moderate consistent gait deficits Grade 4: Severe consistent gait deficits Grade 5: Recumbent

Question: Stringhalt is a nervous disorder which affects the legs of which animal?
Answer: Horse