Tying up also known as Exertional Rhabdomyolysis (ER) is a muscle disorder. Tying up is when the muscles in the horse’s back and hindquarters cramp. This can be caused by a lack of oxygen to the muscles and lactic acid build-up in the muscles. Tying up can cause horses mild to severe pain and stiffness, which can make it extremely difficult for them to move and if not treated can cause lasting muscle damage.
- Struggling to move - if a horse is struggling to move and seems stiff through its hind end, it could be tying up. Stop exercise immediately and walk or transport (if out hacking) the horse back to their stable, do not force them to move as this can cause more damage.
- High temperature and sweating - a horse that has a high temperature and is sweating unexpectedly could be tying up. This can be confused with colic signs.
- Dark urine - a horse with dark brown or red coloured urine is most likely tying up. This is a sign of myoglobin (a protein found in muscles) being released from damaged muscles transferring from the horse’s blood to their kidneys and can cause rhabdomyolysis (long-term kidney problems).
- If you think your horse is tying up call your vet.
- Keep your horse warm with plenty of rugs and ensure they have access to water, this will help keep muscles warm and restore electrolyte balance.
- If the horse is comfortable walking, walk around to prevent further stiffening of the muscles. If the horse is struggling or reluctant to move do not do this as this can lead to further muscle damage.
- To help prevent tying up ensure your horse is properly warmed up and cooled down before and after exercise.
- Ensure an extra-long warmup and avoid strenuous exercise if your horse has had multiple days off in a row.
- If your horse is having a day off, if possible, turn them out and if not ensure they leave their stables for at least two ten-minute leg stretches a day.
- Providing a high fat, low carbohydrate diet with added vitamins E, selenium, and antioxidants can help prevent tying up.
- If your horse is fed large amounts of hard feed, and you know it’s not going to be worked, consider decreasing the amount of hard feed it gets.