What is Tying Up? 

“Tying up” or as it is officially known Equine Rhabdomyolysis (ERS) or Azoturia, is a muscle metabolism condition found in horses, commonly during or after exercise. This often-painful condition causes prolonged camps and tightening of the muscles in the hindquarters. When these muscles fail to relax this causes pain and stiffness, with the most common clinical sign being muscular stiffness. Clinical signs in each case can range from very mild to severe, some horses may seem reluctant to stride out properly whereas others may be unable to move at all. Horses can also be seen stretched out as if they were trying to urinate and may also paw the ground.  

In many cases ERS is the result of underlying muscle conditions such as Polysaccharide Storage Myopathy (PSSM) or Recurrent Exertional Rhabdomysis (RER), however tying up can also happen in horses with no apparent underlying health issues.

Causes?  
Tying up can affect horses/ponies at any stage of their life even if no underlying muscle condition is present.  

The main cause of tying up for those without an underlying muscle condition is due to nutrition and management practices. Common causes are high starch/cereal diets, low forage intakes, lack of exercise or turnout time, overfeeding or electrolyte imbalances.

For those with a muscle condition the primary cause of tying up is less avoidable, however, nutrition and management practices like those listed above can still play a vital role in managing the condition.  

PSSM results in excess accumulation of glycogen in the form of sugar stored within the muscles.

PSSM can often be triggered or exacerbated by the poor management practices listed above as well as a high body condition score, with good doers being commonly prone to the condition.

RER has a variety of causes such as hormonal imbalances, lactic acidosis, electrolyte imbalances and vitamin E/selenium deficiencies. The main cause that has been identified for this type of tying up is a disorder of muscle contractility or excitation.  

How to manage those prone to tying up?  

• Ensure horses are kept at a body condition score (BCS) of 3 on the 5-point scale.  

• Increase forage intake, were possible allow ad lib feeding. Forage should not be restricted to any less than 1.5% of bodyweight as a minimum.  
• Soaking or steaming hay to reduce the water-soluble content (sugar).
• Ideally having the forage tested to allow a low WSC hay to be chosen.   
• Provide a balanced diet that meets all nutrient requirements. 
• Ensure to feed a low starch complete feed.  
• Do not increase feed in anticipation of increased work, the diet should be increased gradually as workload increases. 

• Maintain the electrolyte balance. 
• Maintain a regular exercise program, avoid long breaks between training days.  
• Provide as much turnout as possible.  
• Ensure to correctly warm up and cool down you horse prior/post exercise.  
• Aim to reduce stress.  

The Bluegrass Extra-Pro Range has been designed to suit those that “tie up”. The Extra-Pro Range includes Re-Leve, Re-Solve and Re-Lite Cube . All of which are complete feeds, which are low in starch, low in sugar and high in fibre. They are all fortified with Stamm 30 which provides high quality proteins, vitamins, and minerals, essential in ensuring muscle health along with providing a balanced diet. They also contain natural vitamin E which promotes rapid recovery from muscle soreness and injury.

Contact the Bluegrass Horse Feed helpline to speak with one of our nutritional advisors for more information on feeding those prone to tying up. For an individually formulated diet, head to our website and fill out a Diet Request Sheet where our team members will create a diet tailored to your individual horse’s needs.