The stop/start of winter exercise schedules can significantly increase the likelihood of a horse tying up. This complex condition is better understood than ever before, but episodes can still be alarming and good first aid and follow-up management are needed. Your vet should be involved every time the condition occurs as well as throughout the recovery period.
If an episode happens, stop exercise immediately. If it is severe, the horse may require veterinary treatment on the spot, or more likely, will need to be transported home. In severe cases, the muscle pigment myoglobin escapes into the blood, and horse passes, with some difficulty, discoloured urine.
Once home, the horse should be kept warm, stabled, rugged and offered hay, water and electrolytes. Concentrates should be high in fibre and low in energy.
Once the immediate muscle pain has subsided and the urine is clear, gentle exercise — being led out in hand or turned out (again, well rugged) — encourages blood flow to the muscles and begins repair.
Blood tests taken at the time of the episode help gauge severity; the muscle enzymes creatinine phosphokinase (CK) and aspartate aminotransferase (AST) rise in relation to the level of muscle damage.
Mild cases can restart work after two to three days, but with more severe damage, work is off the agenda until the muscle enzyme results have dropped to within acceptable limits. CK levels rise and decline quickly after an episode, AST values rise over 24-48hr and decline over two to three weeks.
When work resumes it should be daily, increasing steadily in intensity and duration. Avoid schooling, lungeing, the horsewalker and hills in the short term as the muscles will not be up to such intense work for a while.
Preventing an attack
- Common triggers include: not reducing feed on days of rest; returning to work after prolonged box rest; and overexertion
- Minimise stress: keep to a regular routine and avoid individual stresses that wind up your horse
- Make sure you warm up and cool down the horse gradually before and afterwork
- Keep dietary fibre levels high at all times, and starch and sugar as low as possible; provide high antioxidant levels in the diet, principally vitamin E (minimum 1,600mg/day) and selenium (minimum 2mg/day)
- Electrolytes: at the core of tying up is electrolyte transport in the muscles. Using salt (2oz/day) and electrolytes (after extreme work) means that they are amply supplied in the diet at all times
- Keep records after an episode — being aware of what triggered it is often the best way of preventing a recurrence