Tying Up in Horses

Tying up in horses is commonly used to describe horses that are stiff and reluctant to move due to pain originating from the muscle groups within the back, pelvis and hind limbs, it may also be accompanied by excessive sweating, increased heart rate and respiratory rate. Tying up in horses may also be known as; Monday morning disease, Azoturia and Paralytic myoglobinuria.

Tying up can be classed as;

  1. RER- Recurrent Exertional Rhabdomyolysis
    • RER is often seen in Thoroughbreds, Standardbreds and Arabians
    • It is most likely due to the inability to regulate electrolyte levels in skeletal muscle, affecting muscle contraction
    • Is more prevalent in fillies with alert temperaments (>20%)
    • RER has been found to affect approximately 4.9% (USA), 5.4% (AUS) & 6.7% (UK) of racing Thoroughbreds.
    • A survey 69 farms within KSA concluded the prevalence of tying up as being 4.5% (Al-Ghamdi, 2008)
    • High-performance exercise in hot, humid climates may elicit sporadic ER due to the degree of fluid and electrolyte loss
  2. PSSM- Polysaccharide Storage Myopathy (PSSM)
    • Most commonly found in Quarter horse-related breeds, draft horses and Warmbloods
    • PSSM is a heritable trait which results in insulin sensitivity and the abnormal accumulation of glycogen within skeletal muscle
    • May be identified by muscle biopsy and the presence of abnormally high glycogen concentrations – 1.5 – 4 times higher than a normal horse
    • The accumulation of sugars within the muscle tissue may occur gradually over a period of up to 18 months
      • Genetic carrier may not present signs of PSSM due to prolonged glycogen accumulation

Indicators of tying up in horses

  • Episodic tying up is associated with poor performance, reluctance to move and a significant elevation in muscle enzyme levels
  • Blood enzyme indicators:

Creatine Kinase (CK) and Aspartate Transaminase (AST)

  • CK is a short term muscle enzyme used as an indicator of recent (peaks at 6-12 hours) muscle tissue damage. >400IU
  • AST is a muscle enzyme which may remain elevated for days-weeks following CK elevation. >1,000IU
  • High myoglobin levels may be found in the urine as a result of muscle fibre breakdown, giving a coffee coloured appearance
  • Clinical signs usually arise shortly after the onset or commencement of exercise, during times of stress and/or excitement

What horses are at risk of tying up in horses?

Risk factors associated with tying up include;

  • Dietary excess of soluble carbohydrates (e.g. starch and sugars)
  • Frequency of exercise or changes in exercise routine
  • Heritability
  • Vitamin E and selenium deficiencies
  • Degree of fluid and electrolyte loss
    • General electrolyte deficiency
    • Calcium regulation

Things that can be implemented to reduce the potential/severity of tying up in horses

 Ranvet’s BC 5 Amino Acid Paste

  • Branch chain amino acid (BCAA) paste containing 5 BCAA’s
    • L-Leucine: inhibits the breakdown of muscle proteins
    • L- Isoleucine: Powerful anti-oxidant which acts to detoxify peroxides
    • L-Valine: Improves energy metabolism and protein synthesis
    • L-Glutamine: Facilitates greater concentrations of glucose availability to the brain, nervous system and muscles
    • L-Carnitine: Essential for the conversion of fats  into utilisable energy
  • BCAA’s are considered ‘essential’ amino acids and must be obtained within the diet and are unable to be synthesized
  • Are found in high levels within muscle tissue
  • BCAA’s are rapidly utilised by muscle cells during intense exercise

For more information on tying up in horses, please feel free to call us Toll-Free on 1800 727 217. We also have a tying up suggested diet available on our website- click here to view this diet. 


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