Horse Lameness (Equine Lameness)

Horse Lameness medical terms: Founder, Laminitis, Ataxia, EPM protozoa, Rhabdomyolysis, Chondroprotective

What is Horse Lameness? Horse lameness, or equine lameness in horses is mild to severe loss of ability to move normally that can be caused by problems in bones, muscles, nerves, tendons, ligaments, the brain, circulation, and metabolism. That’s right. Almost anything can affect a horse so that it appears lame. The majority of lameness problems occur in the foot. Horse lameness can occur suddenly or gradually. Lameness can increase in severity or never change. Lameness can resolve on its own or can require veterinary intervention. Fortunately, there are many ways to decrease the likelihood that lameness will develop, including having annual visits with an equine veterinarian. Small animal veterinarians who attend meetings of the American Association of Equine Practitioners may also provide helpful advice.

Who Becomes Lame?

Horses, and all members of the equid family (zebras, donkeys, mules) are affected by lameness—from two-foot dwarf miniature horses to nine-foot draft horses. Perhaps equine lameness is most common in horses repeatedly performing maneuvers or running at maximum speed: thoroughbred racehorses, rodeo horses, dressage and event horses. Lameness also occurs in slowly moving donkeys, mules, and backyard ponies.

What Causes Horse Lameness?

Horse lameness can be caused by anything that affects nerves, muscles, joints (tendons, ligaments, bone), and hooves. Among the causes are repetitive injury, founder (explained below), infection, protozoa (a tiny parasite), poor confirmation, tooth problems, obesity, and poor nutrition. The single biggest cause of lameness is hoof problems. Hooves are so crucial to equine movement that the adage, No Hoof No Horse, is part of the equine creed.

Repetitive injuries can cause horse lameness : These occur with racing, timed events (barrel racing), stall and paddock vices (weaving). The more weight on the horse, the younger it is when activities begin, or the more incorrect its conformation, the more likely that repetitive events will cause lameness.

Infection can cause horse lameness: Infections attacking the brain or nerves can cause horses to lose their balance (ataxia) and be unable to walk normally. Ataxic horses stumble and move unevenly, unable to make normal forward or backward progress. Among the infections that cause ataxia are rhinopneumonitis (rhino); West Nile Virus (WNV); and a parasitic protozoal infection, Equine Protozoal Myelitis (EPM). Tetanus, a bacterial infection, can cause stiff, jerky movements. Tetanus will also stiffen the muscles of the jaw so the horse cannot eat.

Poor conformations can cause horse lameness: Horses with poor conformation frequently become lame. In these horses, the skeleton is not aligned and angled properly so that too much stress is put on the joints. Joints become painful and arthritic. The heavier a horse, the younger it is when it begins training, and the more repetitive its training, the greater impact poor conformation has in its performance. All things being equal, horses with the healthiest conformation have the fewest issues with lameness. Horses with healthy conformations have shoulder angles at 45°, front pastern angles at 45-50°, and back pastern angles of 50-55°. Correct conformation puts 60-65% of a horse’s weight on its forelimbs.

Tooth problems can cause horse lameness: Horses with tooth problems can become lame. This is easy to understand if you picture the horse balanced around a gyroscope in its head. The gyroscope includes the jaw and temporal-mandibular joints. Horses with tooth problems put tension on their temporal-mandibular joints and hold their jaws unevenly. If the jaw is uneven, the head is uneven, the internal gyroscope is uneven, and the spine is misaligned. This misalignment leads to uneven stride and lameness.

Poor Nutrition can cause horse lameness: Horses not fed properly can become lame. This includes horses:

• not receiving zinc, biotin, copper, and protein to strengthen hooves
• not receiving Omega 3 fatty acids to provide hoof resilience and prevent hoof cracks
• consuming too much selenium and developing hoof cracksr
• consuming too many simple carbohydrates, such as found in sweetfeeds

Zinc, biotin, copper and protein help strengthen the hoof wall, which is built of parallel fibrous structures called lamellae. Without strength the hoof chips away and cracks. Omega 3 fatty acids help give the hoof flexibility and resilience. Selenium is essential, but only in small amounts. Horses consuming too much selenium develop hoof cracks that encircle the hoof and can cause the entire hoof to slough off.

Sweetfeeds flood the system with rapidly absorbed sugars, which promote muscle damage (rhabdomyolysis) when the horse is worked the next day. Rhabdomyolysis is so common it has several names: Monday Morning Disease, Equine Polysaccharide Storage Myopathy (EPSM), and shivers. Genes linked to rhabdomyolysis are found in draft horses and draft mules, but any horse can develop the problem. While horses with rhabdomyolysis are not lame, they walk stiffly and in pain. With severe rhabdomyolysis, horses cannot move at all.

The articles here were answered by a variety of pharmacists and veterinarians   1 Date Category Topic

 

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