Q: My horse recently experienced an episode where he tied-up. I’d like to know if I can improve his diet in some way to make his muscles function a little better. What principles should I follow for doing this?
A: Tying-up, the common name for exertional rhabdomyolysis, is a broad term used to describe a wide variety of muscle disorders that affect the performance horse. Several specific disorders fall under this umbrella term. Typical signs of tying-up include a horse who becomes stiff, sweats and doesn’t want to move.
When a horse is in the acute recovery phase after tying-up, he needs high-quality hay and a fully balanced diet low in starches and sugars. For horses in light to medium work, a good-quality balancer is a great option. However, to make sure that you still match his current needs and workload without providing too much starch and sugar – especially if he is in heavy work – you may need to add alternative energy sources like oils and proteins and digestible fibre like sugar beet. Another option for horses in heavy work would be a compound feed that is low in starch, providing less than 1g per kilogram of body weight per meal in starches and sugars. In a horse who weighs 500kg, this means less than 500g starch per meal, so if you feed food made up of 10% starch, at a feeding rate of 100g per 100kg of body weight, your horse will get 50g of starch.
A feed containing natural antioxidants can also support muscle health. The two most relevant antioxidants in these horses are vitamin E and selenium. It is important to make sure that your horse receives enough of these to support his muscle health and to mop up any by-products of oxidation that can be harmful to muscle tissues. The doses of vitamin E and selenium need to be calculated quite carefully, so it may be worth speaking to your equine nutritionist or vet to work this out. Selenium is particularly toxic if given in excess, so you need to be careful with this.
Finally, supplementing your horse’s diet with electrolytes, which are needed for most bodily functions, will also help most horses in this situation. Electrolyte imbalances can cause dehydration, fatigue, muscle weakness, and general poor performance, which can exacerbate tying-up symptoms. Speak to your vet or equine nutritionist, but it is advisable to give these horses electrolytes daily in most cases.