Tying Up In horses: Management and Prevention


horse performing regular exercise to prevent tying up

One of the biggest concerns in the equine industry is horse health. When our horses are not feeling their best, we try to find out why. One of the scariest scenarios is when we see or feel our horses suddenly freeze up and stand in pain. Your horse is experiencing a severe muscle spasm called tying up. This is your opportunity stop exercising and to call your vet.


Below, we will discuss more details about tying up and how you can help your horse!


What is tying up?

Tying up in horses affects the heavy muscles in the horse’s back and hindquarters. The condition is called tying up because the affected horse could not move due to severe muscle cramps. It is also known as Equine Rhabdomyolysis, Azoturia, Monday Morning Disease, or set-fast.

horse tying up with muscle tension
Photo credit: Southwest Equine Veterinary Group

In tying up, a horse basically suffers from muscle cramps that result in muscular stiffness. It usually occurs after exercise when the horse is given rest, that is why it is sometimes known as Exertional Rhabdomyolysis Syndrome.


Tying up develops due to irregular exercise and feeding schedule. The mechanism of contraction and relaxation of muscles is disturbed. The muscles are unable to relax after a contraction that ends in stiffness. It might cause the breakdown of muscle and myoglobin (dark red protein in muscles) is released. That is why the urine of such horses is dark red because myoglobin is released into the urine from the kidneys.


This condition can affect horses of any breed, gender, or age regardless of underlying pathology. However, a study suggested that female horses are more affected by tying up than males. The most common cases of ‘tying up’ are seen in Quarter breeds, Thoroughbreds, Arab breeds, and Standardbreds.

horse muscle group diagram

Types of Tying Up

There are three types of tying up seen in horses. Let's discuss them so you can get a thorough understanding.

  • Sporadic form: It is the general muscle cramping experienced by a horse who did not have a previous episode of tying up. It is also referred to as acute tying up. It develops mainly due to overexertion.

  • Chronic form: Muscle cramping in horses who had suffered from recurrent episodes of tying up. Such horses experience tying up even with light exertion. It can lead to serious muscle damage.

  • PSSM or Polysaccharide Storage Myopathy: It is muscle cramping that is caused by the accumulation of glycogen in the muscles. It can occur with or without genetic mutation. The mutation occurs in the gene which is responsible for making glycogen.

Causes of Tying Up in Horses

Let's move on to the causes of tying up. Why does tying up occur in horses? Here are some possible causes of tying up.

horse sweating losing electrolytes can cause tying up
  • Overfeeding a horse, especially during periods of rest is the most common cause of ERS. Too many carbohydrates are certainly not good for the health of your equine. It can cause severe muscle damage due to acid base imbalance.

  • Electrolyte depletion: Low fiber diet can deplete electrolytes in the horse’s body which are necessary for the regulation of muscle contraction. Otherwise, the muscle will only remain contracted without relaxation.

  • Increased glycogen stores: It may be due to gene mutation as in Type I PSSM. Or some dietary factors like a high starch diet can cause glycogen accumulation which further causes muscle breakdown.

  • Over exertion: When a horse is trained after a period of rest and is fed a high carb diet, he can be affected by Sporadic form of tying up.

  • Impaired calcium to phosphorus ratio: It can cause abnormal muscle contractions.

  • Hormonal imbalance: Horses who have hypothyroidism are more likely to suffer from tying up.

  • Vitamin E and Selenium deficiency: Often a cause of muscle degeneration due to poor muscle function.

  • Dehydration: It decreases blood flow to the muscles which results in cramping.

Signs and Symptoms of Tying Up

Here are some signs that you might observe in your horse while it’s suffering from tying up.

  • Very first sign you’ll notice in your horse is that it's unable to move

  • Muscles of lumbar and sacral region are stiff

  • Body temperature is raised up to 40 degrees

  • Horse urinates frequently or you may notice dark red colored urine

  • Horse is unable to move the back and hind limbs

  • Muscles are hot to touch

  • High Pulse rate

  • Abnormal changes in its behavior

  • Horse is stuck to the floor or unable to get up.

  • High respiration rate

  • High sweating

  • In severe cases, the horse may collapse when trying to move

horses tying up and muscle spasms
Horse tying up (L), Horse with tight muscles (R) Photo credit: Deben Valley Equine

How to manage an episode of Tying up?

When your horse gets an episode of tying up, you can follow this protocol:

  • Immediately stop training or exercising

  • Call your vet ASAP

  • Move horse to stall if he can walk, don't force it!

  • Remove feed and hay if it is currently accessible.

  • Provide small amounts of water if the horse is still hot. Once the horse is cool, you can offer free access to water.

  • Your vet can suggest calming and pain relief drugs.

  • Allow access to a small paddock once the horse is able to move again.

  • Watch for any signs of tying up again in the next 24 hours. If it occurs again, your vet may need to assess for other conditions.

How can you prevent tying up?

Tying up can be extremely painful and every horse owner wish to prevent this painful condition from occurring. Here are some steps you can take for the prevention of tying up in your horse.

diet can help prevent onset of tying up

Nutrition & Diet management

As mentioned before, the main cause of Tying up is overfeeding correlated with overexertion. So, this is the first and foremost thing you should consider for your horse to prevent tying up.

  • Avoid overfeeding your horse. Always measure the food according to the horse’s body weight and nutritional requirements.

  • Feed a low starch diet. Too much starch can disturb the digestive system. The same goes for carbs. Try to limit carbs from its diet.

  • While you check the quantity, make sure that you’re feeding a good quality diet.

  • Reduce body weight if it is not maintained under the average Body Condition Score.