02/26/2026
Following on from a previous post about behaviour and pain, how interesting is this? A recent paper describes a 14-year-old Welsh competition pony presented for explosive, dangerous behaviour in canter, just three weeks after a change of ownership. She was referred for investigations and later found to have malformed spine and an extra rib!
Previously, the mare had competed in low-level dressage and showjumping. On arrival with her new owners, a mild hindlimb lameness was noted, which didn't resolve with rest - what escalated was her behaviour under saddle. On examination she had:
• Marked epaxial muscle atrophy over the mid-thoracic spine
• Visible right-sided scoliosis
• Severe restriction in thoracic flexion and extension (T9–T12)
• Pain reactions on palpation and mobilisation
• Stiffness and difficulty maintaining canter leads
• No neurological deficits
Radiographs revealed abnormal vertebral bodies, partial fusion between T11–T12, an additional malformed spinous process, and mild kyphosis.
Postmortem CT confirmed complex congenital thoracic malformations, including:
• Scoliosis centred at T10
• Partial vertebral fusion
• Abnormally shaped vertebral bodies
• A malformed additional rib with altered rib-to-spine articulations
• Degenerative changes in multiple articular and costovertebral joints
In simple terms: the spine was structurally abnormal from birth. Over time, altered biomechanics likely increased mechanical stress, restricted motion, and contributed to pain, particularly at canter, where spinal motion demands increase significantly.
What makes this case especially important is the timeline: the pony had worked previously - she had competed. The behavioural escalation followed a change in ownership and management which the authors suggest could be due to compensatory mechanisms gradually failing, or that subtle discomfort had previously been attributed just to temperament.
This paper reinforces several key points:
• Not all back pain is kissing spines.
• Not all pain presents with neurological deficits.
• Structural abnormalities can exist in mature, functional horses.
• Behavioural change (especially after changes in rider, workload or management) deserves investigation.
Importantly, the authors stress that severe imaging findings alone are not an automatic indication for euthanasia. Findings should always be interpreted in context and with correlation to clinical symptoms. But when behaviour changes, particularly in a previously “coping” horse, it’s certainly worth asking why. This paper also highlights how sometimes the story starts long before the behaviour becomes impossible to ignore - right back when the horse was developing in the womb!
If you have any concerns about your horse's behaviour or think a work-up is needed, do feel free to contact us to discuss and we can arrange a visit with Emiliano!
Read the full paper here: https://www.sciencedirect.com/science/article/pii/S0737080626000365?dgcid=author
