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Medical Index
First Posted: May 2007
Apr 10, 2019

Tying-up, Azoturia, Monday Morning Disease, Exertional Rhadomyolysis

by Debora Johnson
Diseases that can be caused by dietary origin
Tying-Up: Current Diagnosis and Nutritional Management
Selenium and Vitamin E to Alleviate Signs of Tying Up

Latest Update: Tying-Up in Horses: Where Do We Stand? Posted by Stacey Oke, DVM, MSc | Apr 10, 2019 | Anatomy & Physiology, Breed-Specific Health Issues, Draft Breeds, Exercise-Related Conditions, Injuries & Lameness, Lameness, Muscle and Joint Problems, Musculoskeletal System, Nutrition-Related Problems, Polysaccharide Storage Myopathy (PSSM), Quarter Horses, Special Needs Nutrition, Sports Medicine

Update:"'The repository of over 3,000 muscle and DNA samples from across North America at the Neuromuscular Diagnostic Laboratory, University of Minnesota, has proved to be invaluable in further defining the histological, clinical, epidemiological, pathological, and genetic basis for specific muscle disorders in horses."

Valberg and other researchers are unraveling the genetic basis for tying up. As equine genome mapping techniques progress, DNA-based tests are increasingly becoming part of the diagnostic approach to muscle disease in horses. Four DNA-based tests for muscle disorders in horses are available. Individual tests identify hyperkalemic periodic paralysis (HYPP), glycogen branching enzyme deficiency (GBED), malignant hyperthermia (MH), and type 1 polysaccharide storage myopathy (PSSM1). DNA diagnosis uses hair roots or blood samples, and provides a less invasive and more accurate diagnosis than histological interpretation of muscle biopsy.

Valberg mentioned that advances in establishing accurate diagnosis for the cause of tying-up are invaluable because precise diagnosis '(1) defines the likelihood of recurrence of the condition; (2) establishes reasonable expectations for the horse; (3) provides for the appropriate selection of targeted dietary therapy and exercise regimes; and (4) determines the likelihood that the horse will pass on the disorder to potential offspring.'

Tying-up is a generic term commonly used to describe muscle disease in horses. Other references to the same set of symptoms may be exertional rhadomyolysis, azoturia, Monday Morning Disease, and Market Day Disease. Monday Morning Disease got its name because when a horse had been performing his regular hard work and was given a day off, but his diet had not been reduced; he tied-up on Monday morning when he was returned to work."

Profuse sweating, tight muscles in hindquarters, muscle cramping

  • Stiff Gait
  • Reluctance to move
  • Profuse Sweating
  • Tight muscles in the hindquarters
  • Muscle cramping generally
  • Elevated heart rate
  • Increased respiratory rate
Testing for Tying-up, etc.

Call your vet immediately and blood will be drawn and tested. If your horse is tying-up there will be certain markers (elevated serum levels) in the blood. Basically three serum levels are checked.

  • Creatine Kinase (CK)
  • Lactate dehydrogenase (LDH)
  • Aspartate aminotransferase (AST)

Elevations in serum levels of muscle enzymes are used in the diagnosis as well as visual symptoms. Enzyme elevations are indicators that there has been cell damage to the muscles. Sometimes you will notice that your horse's urine has a reddish or brownish tint.

Some horses will have this happen only one time. These horses are referred to "sporatic" cases. Others will continue to have this happen. They are considered "chronic" cases.

Sporatic Cases

For horses tying-up sporatically the following may be potential causes:

  • Not fit
  • Depletion of electrolytes
  • Hyperthermia
  • Respiratory disease
  • Lameness
  • Sudden temperature changes (Warm to cold)
  • Stress of travel
  • Stress of noise
  • Mares in estrus that are nervous are prone to tying-up
  • Nervous fillies are prone to tying-up
  • Change in diet with being gradual
  • Irregular stop-start exercise
  • Horses need to be warmed up before being exercised
  • Horses have to be cooled down after exercised
Chronic Cases

Research has shown that there are several reasons that horses may be chronically tying-up. There is a disorder which affects the horse's muscles. The muscles go into spasm or contraction. The second involves a problem with how the horse metabolizes carbohydrate. Often heavier breeds such as Quarter Horses, Warmbloods, and draft breeds have polysaccaride storage myopathy (PSSM). Research has shown that this is an insulin problem. Sugar or glycogen, is stored in the muscle which causes a metabolic problem. The horses tend to show signs of typing-up and are often calm in disposition. Do not feed them grain or sweet feed, exercise them daily, do not let them be inactive for any length of time, feed them rice bran (fats) to stabilize their blood sugar. This decreases storage of fats in the muscles. Horses that show repeated signs of tying-up are classified as "chronic" cases.

I have had two horses over the years with a tying up problem. I found that if I cut all sweet feed or anything rich in carbohydrate in the horse's diet, they did much better. Also, I added a selenium supplement to the diet, every day. I did not buy this over the counter, but rather, bought it from my vet. When trail riding, I always carry banamine paste in my saddlebags in case my horse has a problem. One of the two horses had an episode and coliced from the pain. We almost lost him. Thus, the banamine. Of course, always ask your vet. I would also like to add, here, that Virginia is deficient in the mineral selenium. Because of this, I still make sure that the horses have enough selenium. My two current horses have never had this problem. Wherever you live, ask your vet if your area is selenium deficient.

Update: Potential Biomarker for Tying-up Found "...In an equine study using "proteomic" technology that systematically analyzed the proteins in skeletal muscle biopsies, a research team from The Netherlands identified a form of the protein creatine kinase that could be a marker for acute tying-up in horses.

'Tying-up or rhabdomyolysis in horses is a serious condition that is characterized by obvious discomfort, abnormal muscle stiffness, and difficulties to move with short strides, muscle hardening/contracting with hindquarter spasms, and an elevated pulse and respiration. Eventually it can led to death,' wrote the group. The team, led by Edwin Mariman, Professor and Dr E.C.M., performed this research at the NUTRIM School for Nutrition, Toxicology, and Metabolism at Maastricht University Medical Center and the Department of Equine Sciences at Utrecht University in the Netherlands...."

Update: Selenium and Vitamin E to Alleviate Signs of Tying Up

"Exertional rhabdomyolysis, otherwise known as 'tying up' is a term used to describe a variety of muscle disorders in the equine athlete. Horses affected by tying up have varying degrees of muscle cramping or muscle soreness, with the more severe cases accompanied by elevated respiratory and heart rates, dark colored urine, and reluctance to move or stand.

A balanced diet, including vitamins and minerals, is just one factor in the treatment and prevention of tying up. Here are some ways that two specific nutrients, selenium and vitamin E, can help prevent or alleviate symptoms of tying up: ..."

For More Information:

Fit To Be Tied: Symptoms, Causes and Treatment For Tying-Up in Horses
It Isn't Just 'Tying Up' Any more

Medical Index