Lameness in horses is well recognised, but interpreted differently by different people. It describes the horse’s gait being adversely affected by pain or a restriction in the normal range of movement and should never be ignored. This pain or restriction can originate in the hoof, in the leg or elsewhere in the horse’s body, such as the back or neck.
Lameness can range from a subtle change in gait, which is often missed by the untrained eye, to the horse being unable to carry any weight on the affected limb.
Lameness has been identified as the most common reason for older horses to be put down¹.
Lameness in horses: Causes | Diagnosis | Prognosis
Causes of lameness in horses
Causes of lameness in horses are wide ranging and include, but are not limited to, the following conditions:
- Laminitis
- Tendon damage
- Ligament injuries
- Bruises or abscesses in the hoof
- Fractures
- Poor hoof balance
- Back and neck problems
- Degenerative joint disease
According to the 2015 edition of the National Equine Health Survey², lameness is three times more likely to be caused by conditions such as osteoarthritis, also known as degenerative joint disease, than problems in the foot.
If your horse is showing signs of lameness it is important to involve your vet at the earliest possible stage. This may save you time, money and frustration by diagnosing and treating the problem early, as well as potentially preventing further damage from occurring. In this way you can help prevent small niggles from becoming major long-term problems.
It is important to appreciate that low-grade — even sub-clinical — lameness may significantly compromise a horse’s performance, so if a horse becomes unwilling to perform certain movements that it was previously willing to do, this may be the earliest signs of a lameness problem.
Diagnosing lameness in horses
Being able to identify the reason a horse is lame is an ongoing challenge for equine vets, particularly with subtle and intermittent problems. Lameness is often multi-faceted and can affect more than one limb, or area of the body.
A thorough physical examination of the limbs, feet, neck and back, trotting the horse up in a straight line and on a circle on soft and hard surfaces, flexion tests plus nerve blocks are all common ways to pinpoint the location of the problem. Vets may also use a range of diagnostic tools, such as X-rays, ultrasound and nuclear scintigraphy (bone scans), MRI scans, as part of a lameness workup.
To support the vet’s eye, a number of computer systems that use wireless sensors to track the movement of the horse’s poll, pelvis and the flight of the horse’s limbs have been developed to help identify where there are gait abnormalities3.
Levels of lameness are normally graded on a sliding scale, which can run from zero to five or zero to 10, depending on your vet. These gradings tend to be subjective and so are best used to monitor improvement or deterioration in a horse’s lameness, rather than to compare lameness among different horses.
Dr Sue Dyson, recently retired head of clinical orthopaedics at the Animal Health Trust (AHT), has undertaken extensive research to identify the external signs that a horse is in pain. As part of this work, 24 behavioural markers were consistently linked to lameness4, with the presence of eight or more being a likely indicator of musculoskeletal pain. Lame horses displayed an average of nine of the markers.
Previous research designed to investigate why saddles slip had shown that nearly half of sport horses thought to be sound by their owners were actually lame5. This work is enabling Dr Dyson to develop an ethogram [table of behaviours] to help identify lame horses with the intention of producing a functional guide for horse owners to use in the future.
Prognosis
Very few horses will enjoy their working lives without taking a lame step, in the same way that few active people will live without the odd ache or pain. In many cases a minor lameness can be rectified reasonably simply and quickly, but as the causes of lameness are so varied, the prognosis will depend on the type of issue found.
Regular and effective farriery is important in avoiding lameness as well as overall fitness and good management for every horse. The old cliché of “no foot, no horse” still holds true.
References
1. https://www.ncbi.nlm.nih.gov/pubmed/21733586
2. https://www.horseandhound.co.uk/news/joint-problems-most-likely-to-cause-lameness-509579
3. https://www.ncbi.nlm.nih.gov/pubmed/21879972
4. https://www.horseandhound.co.uk/news/sue-dyson-lameness-behaviours-638363
5. https://www.horseandhound.co.uk/news/half-horses-lame-saddle-slip-survey-428728
Also: https://onlinelibrary.wiley.com/doi/full/10.1111/evj.13162
