McKee-Pownall Equine Services | Health Care FAQ

Health Care FAQ

What is Tying Up?

Tying Up (Azoturia, Exertional Myopathy, Exertional Rhabdomyolysis)

In its mild form, this is a relatively common condition that affects the muscles of the horse's hindquarters and back. Inflammation of these muscles causes pain and stiffness.

"Monday Morning Disease"

Tying up is usually seen in horses on high energy diets after a rest from their normal exercise routine. It used to be called 'Monday Morning Disease' because it commonly affected working horses after their rest day on Sunday.

In some particularly susceptible horses, notably fillies, even a reduction in exercise for one day can result in the horse becoming tied up on resumption of normal exercise.

What are the Symptoms?

Mild Cases

Mild cases of tying up just appear 'stiff behind' after exercise. Usually both sides of the body are affected equally so the horse does not actually appear lame.

Severe Cases

In more severe cases the horse may be reluctant to move and show signs of pain such as sweating and scraping the ground. Some may be thought to have colic.

Very severe cases may be unable to move and may even collapse.

What Should I Do?

If you suspect that your horse is "tying up", stop exercise immediately and dismount.

Detection and First Steps

Sometimes a rider can detect very early signs by a change in action and this should not be ignored. If the horse can walk, return him to his stable. Do not keep him walking as this may worsen the muscle damage. If he is very stiff or unable to walk, get a trailer to transport him to a stable. In moderate to severe cases a veterinarian should be contacted.


Initial treatment consists of anti-inflammatory medications (flunixin meglumine, methocarbamol) and rest. Ensure constant access to fresh water, and electrolyte supplementation is recommended.

Mild Cases

Very mild cases sometimes respond quickly to tranquillization with acepromazine.

Severe Cases

Severe cases may require intravenous fluids and intensive supportive treatment.

Your veterinarian will collect a blood sample to measure muscle enzymes to confirm the diagnosis and to determine the severity of the muscle damage. Follow-up blood samples will monitor response to treatment and confirm when it is safe to resume exercise.

Why Do Horses Get Tied Up?

This is a very complex condition and one that is not completely understood.

Excess Energy Intake

In some cases it appears to be due to excess energy intake, particularly in the form of carbohydrates, relative to the amount of exercise being received.

Electrolyte Imbalance

In other cases, it appears to be associated with changing levels of electrolytes (salts) in the blood. Imbalances in certain minerals and vitamins (especially calcium, phosphorus, vitamin E and selenium) are believed to be involved in some cases.


Other stressful factors such as gastric ulcers, lameness, excitable personality, and estrous cycles can predispose a horse to tying up.

How Can I Prevent Tying Up?


There are several things you can do to prevent tying up:

  • Ensure that your horse's diet is providing him with the right amounts of energy, protein, vitamins and minerals for the job you are asking him to do
  • On 'easy' days, reduce the amount of feed you give your horse to reflect the reduction in exercise
  • If possible, ensure your horse gets some exercise every day, even if this is simply turnout or handwalking


There are many diets available for horses that are prone to this condition that provide considerable energy from fat rather than high carbohydrate. The by-products of fat metabolism are less damaging to muscle than those from carbohydrates.

Branched chain amino acid supplements (BCAA) given prior to exercise and shipping can also provide an alternative source of energy.

Medical Care

Ongoing medical problems such as chronic lameness, difficult heats in mares, and gastric ulcers should be addressed.

Following Tying Up

If your horse has been "tied up" it is important to give the muscles time to recover. This can be monitored using blood tests.

Return to Exercise

A gradual return to exercise after recovery is recommended so that there is no sudden increase to trigger another episode of the condition.

Some horses can safely resume exercise following treatment with the drug dantrolene sodium, given by mouth. This is given approximately one hour before exercise and should be administered until the horse has returned to the level of exercise reached before becoming tied up. Dantrolene carries a fairly long withdrawal and cannot be used when horses are competing.

Recurrent Tying Up

If your horse has a recurrent problem with tying up, your veterinarian can collect samples of blood, urine and feed stuffs, for laboratory testing to determine if there are electrolyte, mineral or dietary imbalances that may contribute to the condition and require correction.