Any abnormality in a horse's gait or stance is generally referred to as lameness. This can be caused by pain, a mechanical problem, or a neurological condition.1 Lameness most commonly results from pain in the muscles, tendons, ligaments, bones, or joints which leads to abnormal movement at the walk, trot, or canter. Lameness accounts for the greatest losses for the equine industry, amounting to hundreds of millions of dollars annually.3 Lameness affects horses of all kinds and at all levels. Unfortunately, many horses experiencing lameness are asked to perform despite their pain because of owners, managers or riders failing to recognize the condition.

Lameness is actually a clinical indication rather than a disease. Mechanical lameness is best described by complete upward fixation of the patella with its characteristic gait abnormality, but can also be the result of fibrotic myopathy of the semitendinosus muscle or of restrictions caused by annular ligaments, adhesions, or severe fibrosis.2

Understanding Lameness in the Horse

Pain-related lameness can be classified as weight bearing (in the supporting leg) or non-weight bearing (the moving leg). Although it is most often observed as a weight-bearing problem, lameness may be composed of both. Supporting leg lameness is generally seen when a horse reduces the amount of time or reduces the amount of force applied to the weight-bearing limb.2 The most easily-recognized clinical signs of lameness are the characteristic head nod associated with forelimb lameness and the rise of the hip associated with hindlimb lameness. Forelimb lameness should be assessed from the front and side, while hindlimb lameness should be assessed from the side as well as from behind.1

Factors that predispose horses to lameness include physical immaturity, developmental orthopedic disease, poor conformation, improper hoof balance or shoeing, adequate conditioning and repetitive stress.2 Other factors include direct or indirect trauma, fatigue resulting in incoordination of muscles inflammation and infection. It is important to correctly determine the cause of the lameness, because the treatment will vary greatly depending on the causative factor(s). Quantitative gait studies have revealed that a large proportion of horses in training, perceived as free from lameness by their owners, show movement asymmetries of equal magnitude to horses with mild clinical lameness,3 and disorders of the locomotor apparatus are collectively the most common reason for equine veterinary consultations.2,3

Lameness in one part of a limb can result in secondary soreness in another area of the same limb and may result in lameness of another limb from overuse due to compensation. Thus, any horse experiencing lameness should be evaluated for secondary lameness even when the cause of the primary problem is evident. 1Secondary lameness is very common in performance horses, but may occur in any breed of horse.

Diagnosing Lameness

For equine veterinarians, lameness diagnosis and treatment is a comprehensive process, requiring an understanding of equine anatomy and physiology, conformation, biomechanics, and medicine. It also requires adaptation in response to changing conditions, horse types and breeds, uses and personalities, and the needs of the owner.1

Generally, lameness exams consist of (1) a careful history, (2) a standing exam (3) an exam in movement, (4) flexion and hoof tester exams, (5) diagnostic anesthesia – nerve and joint blocks, and (6) imaging (e.g., radiographs, ultrasound, MRI). The diagnosis and treatment plan is derived from findings consisting of all of these.1,2

Veterinary treatments used for lameness diagnoses typically include:

• Joint (intra-articular) injections of steroids and other substances to reduce inflammation and pain in an arthritic joint.

• Systemic (oral or injectable) anti-inflammatory drugs and pain relievers to manage multiple pain sources. 

• Surgery (e.g., arthroscopy) is often used to treat certain types of lameness.  Here, repairs are made to the joint surface through several tiny incisions using a small camera and instruments inserted into the joint.2

Meloxicam for Lameness in Horses

In horses with induced lameness from lipopolysaccharide-induced joint inflammation, meloxicam treatment has been shown to result in a reduction in visual lameness scores, a reduction in head movement asymmetry and in a suppression of synovial fluid markers of inflammation, MMP activity and cartilage turnover when compared to placebo. In horses with clinical musculoskeletal pain, meloxicam was more effective in alleviating lameness than vedaprofen. Evidence suggests that meloxicam reduces musculoskeletal pain of inflammatory origin.3

In horses, meloxicam appears to be well absorbed. Elimination half-life in horses given 0.6 mg/kg IV toward the end of laparotomy for colic syndrome was 6.9 hours and 5 hours in horses given 0.6 mg/kg PO once daily for 14 days. Absorption was similar in foals younger than 6 weeks of age, but elimination half-life was 2.5 hours.3

Where to buy Meloxicam 

Meloxicamis available in the U.S. through several pharmaceutical manufacturers and through veterinary custom compounding companies. 

Meloxicam carries numerous potential drug interactions. Please consult your veterinarian prior to beginning any treatment regimen.

FOR RX ONLY: A valid prescription from a licensed veterinarian is required for dispensing this medication.

1acvs.com.

2Merck Veterinary Manual.

3Persson-Sjodin E, Hernlund E, Pfau T, Haubro Andersen P, Holm Forsström K, Rhodin M (2019) Effect of meloxicam treatment on movement asymmetry in riding horses in training. PLoS ONE 14(8): e0221117.