Stringhalt: The Marionette Horse

This is one condition that has perplexed equine veterinarians for centuries. Stringhalt can develop in a horse seemingly overnight with no apparent cause, and often there is no standard treatment. In other words, it can be a horse owner’s worst nightmare. There’s good news, though – stringhalt isn’t a typical lameness. It doesn’t always stem from pain avoidance as many lamenesses typically do, so your horse isn’t necessarily uncomfortable. Stringhalt appears to be a mechanical or neurologic illness – the nerves and muscles aren’t communicating appropriately, and therefore aren’t functioning properly.

What causes stringhalt?

We don’t truly know what causes it. Some forms of stringhalt can be traced to a toxic plant or flower that a horse ate (called Australian Stringhalt – check out the CSU List of Dangerous Plants), but this cause has rarely been described in the US. The condition has also been seen secondary to the following issues: trauma to the lateral digital extensor tendon or muscle, EPM, and Developmental Orthopedic Disease involving the neck vertebra. However, in the majority of cases, the definitive cause is unknown.

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What’s actually happening when a horse has stringhalt?

While the underlying cause is often unknown, the result is that the digital extensor muscles contract excessively. This is seen as a jerk, hop, or otherwise pop of the leg in an unnatural, quick movement. The leg will likely hang for a millisecond before dropping back down. You can often see this motion most clearly at the walk, during transitions, and while your horse is backing up. This motion can become more dramatic over time.

How do we treat stringhalt?

Unfortunately, there isn’t a definitive fix just yet. Traditionally, cutting the lateral digital extensor tendon and a portion of the muscle can work on some horses, or at least provide temporary relief. If toxic plants are suspected, removal from the pasture is indicated. Some have advocated for increasing Vitamin E, and other treatment options are being explored, such as acupuncture. The bottom line is this: there’s still a lot of research to be completed, and we don’t have a foolproof fix yet.

Have a question about stringhalt we haven’t addressed? Ask us questions in the comment section. If you think your horse might have stringhalt, give your local veterinarian a call to help you through the process of diagnosis and treatment.

By Howard Ketover, DVM