With about one in five horses typically suffering an attack during their lifetime, avoiding azoturia in horses is something that all owners would like to do. The condition is now officially known as ERS (equine rhabdomyolysis syndrome), but is also refered to as tying up, setfast and traditionally, Monday morning disease.
It is more prevalent in hard-working competition and racehorses, but is not limited to these types, and an attack can happen to any exercising equine.
Scientific understanding of ERS has disproved the popular belief that lactic acid build-up in the muscles is the cause of the condition, but the myth is still perpetuated. What is true is that susceptible horses have an underlying, most likely genetic, predisposition to ERS, which leads to an attack when some management factor tips them over the edge.
Stress is one of the triggers: it can arise from travelling long distances to a competition, not only from the journey itself, but also due to excitement on arrival.
Dietary stress is another factor. Many incidences are caused by a change in routine that (sometimes without your knowledge) means that the amount of fibre in the diet is reduced. This can happen with an increase in workload, a change in forage or by a horse being too excited to eat before, during or after a competition.
Typical signs are that the horse, usually shortly after the onset of exercise, begins to take stiff, short strides and within a short time becomes reluctant to move. He can sweat profusely.
The horse should be taken home immediately by lorry or trailer if the attack is bad, and the vet called. The vet will treat the symptoms and take a blood test for confirmatory diagnosis.
Only after the immediate muscle pain has subsided should the horse be led or turned out. Both encourage blood flow to the muscles and therefore aid repair. Mild cases can re-start work after two to three days, but with more severe damage, work is off the agenda for a number of weeks.
Avoiding azoturia in horses
- Warm up and cool down the horse effectively before and after exercise, and avoid over-exertion
- Keep stress levels low: try to stick to a regular routine and avoid situations that excite your horse
- Try to maintain a consistent diet and make changes gradually: do not allow a horse to eat lush grass at events if your grazing is poor as this could trigger an attack
- Keep dietary fibre levels high and starch and sugar as low as possible, and cut feed on days off
- Use electrolytes, especially when travel and workload are high
- Give high-risk horses antioxidants that combat the effects of muscle damage: vitamin E (1,600mg/day) and selenium (2mg/day) are effective at muscle level
This feature was first published in Horse & Hound (5 August)