Tying-up, also known as equine rhabdomyolysis, is a painful and sometimes debilitating muscle disorder that affects horses during or after exercise. It involves muscle cramping, stiffness, and in severe cases, muscle breakdown. Horses prone to tying-up need careful dietary and exercise management, especially when it comes to grain intake, non-structural carbohydrate (NSC) levels, and stress control.
What Are the Signs of Rhabdomyolysis (Muscle Breakdown)
Tying-up affects the large muscles of the hindquarters, back, and occasionally the shoulders, causing:
- Painful, hard muscle cramps that don’t relax
- Reluctance to move or difficulty stepping forward
- Shivering, sweating, and increased heart and respiratory rates
- Body temperature up to 40–40.5°C
- Brown or red-coloured urine (caused by myoglobin from damaged muscle cells)
- Signs that resemble colic, but with obvious muscle tightness and stiffness
- Severe episodes can impair kidney function due to myoglobin release, making veterinary support essential.
How Does Tying-Up Present?
Tying-up may develop gradually or suddenly, and it can vary in intensity. It's often triggered under specific conditions:
- Returning to work after rest with a high-grain diet (commonly called Monday morning disease)
- Nervous excitement, travel, or competition
- Overexertion or lack of proper conditioning
- Sudden weather changes or unknown causes
Diagnosis is confirmed through blood tests measuring creatine kinase (CK) and aspartate transaminase (AST), which indicate the level of muscle damage.
Understanding the Three Types of Tying-Up
1. Sporadic Exertional Rhabdomyolysis
- Seen in any horse after intense exercise, dehydration, or high-grain diets
- Often resolves with rest and proper nutrition
2. Recurrent Exertional Rhabdomyolysis (RER)
- Affects mainly Thoroughbreds, Arabs, and Standardbreds
- Linked to excitability and abnormal calcium regulation within muscles
- Triggered by exercise and stress
3. Polysaccharide Storage Myopathy (PSSM)
- Type 1: Involves an insulin sensitivity leading to excessive and abnormal glycogen storage; common in Quarter Horses, Paints, and Appaloosas
- Type 2: Seen in Draft breeds, Warmbloods, and their crosses; causes chronic muscle soreness, reluctance to engage hindquarters, weakness, and muscle wasting
The Role of Diet: Why Low-NSC and Grain-Free Diets Matter
Grain and high-starch feeds can worsen tying-up symptoms, particularly in horses with PSSM or RER. These feeds spike insulin and promote abnormal glycogen storage in muscles.
To reduce the risk:
Low-NSC (Non-Structural Carbohydrate) Diets
- Avoid grain, sweet feeds, and high-sugar forages
- Choose low-NSC alternatives like CoolStance® Copra, a coconut-based feed that's:
Low in sugar and starch
Rich in digestible fibre and cool energy from medium-chain triglycerides
Ideal for horses with PSSM, insulin issues, or prone to tying-up
Naturally high in lauric acid, which supports immune and gut health
Electrolytes, Minerals, and Vitamins Are Essential
Imbalances in electrolytes, magnesium, selenium, or vitamin E can increase susceptibility to tying-up. Make sure your horse receives:
Exercise and Management for Horses That Tie-Up
- Consistent Daily Exercise. Avoid rest days
Implement structured fitness with a proper warm-up and cool-down. Prevent lactic acid build-up and maintain muscle tone
- Minimise Stress and Excitement. Provide ad lib grassy hay to mimic natural grazing behaviour. Limit lucerne to no more than 50% of hay intake. Avoid sudden changes in routine, travel, or high-arousal events
- Feed for Calm Energy. Use cool energy sources like oils or CoolStance Copra instead of grains. Keep sugar and starch low, especially in susceptible horses .
Treatment and Long-Term Care
Always contact your vet at the first sign of tying-up. Treatment may include:
- Anti-inflammatories
- Electrolyte and fluid support
- Muscle relaxants (if necessary)
- Careful monitoring of kidney function
- Controlled reintroduction to work under veterinary guidance
Selenium and vitamin E are vital for horses prone to tying up. They work together to reduce oxidative stress, protect muscle tissue, and aid in recovery after exercise. Horses on grain-free, low-NSC, or restricted grazing diets (often recommended for tying up syndromes like PSSM) are especially vulnerable to deficiencies. Proactive supplementation and correct diet management are key components of a successful tying-up prevention strategy. Choose a product that provides vitamin E in its natural form (d-alpha-tocopherol) for higher bioavailability. Selenium should be provided in a safe organic form (e.g., selenium yeast) for better absorption and safety.
Summary: Managing Tying-Up in Horses
