In 600kg of bone, muscle, fat and attendant tissues, there’s a lot to look at when your horse loses his form. Many conditions that can affect performance might not be visible to the eye, and veterinary investigation will be required initially, although the problem may be solved by other interventions such as physiotherapy or good farriery.

You can’t ignore a review of the nutritional supply from the diet when investigating performance, once the obvious suspects – such as tendons, ligaments, heart and infection – have been ruled out.

Nutritional indicators of health are whether or not the horse is drinking normally (easy to see with buckets, less so with automatic drinkers), whether he is eating up, his droppings are normal, his coat is looking good, he is holding condition and behaving normally.

Vets and nutritionists can work together in detecting the inner failings of the diet. It is possible to conduct blood tests to determine muscle enzymes, fractional electrolyte tests to determine hydration status and scoping to detect lung inflammation, among other things.

Many nutrition-related causes of poor performance, though, may not be revealed via such tests, but only after dietary evaluation. The horse which loses its movement may be a subclinical laminitis sufferer. The horse which regularly runs out of steam might benefit from a review of energy sources together with a revised fittening programme, or from an assessment of respiratory challenge.

Undetectable dusts and pollens may cause lung irritation without evident inflammation. An ongoing gastric ulcer problem may affect temper and willingness to work.

Diet checklist

  • Water. Has anything happened to the water supply, in terms of quality or quantity?
  • Forage. Has it changed in any way recently — a new source or just variable bales? Is it trodden into the bed? Is the horse eating enough? A minimum of 1% of bodyweight as forage is essential for health and performance.
  • Hard feed. Is it the right choice for your horse? Are you feeding too much or too little? Is it good quality and free from mould? Does it match up to the declaration on the bag?
  • Supplements. Are you using appropriate supplements? Are you overdosing? Excess vitamin A, for example, can affect hoof quality and reduce appetite, and excess selenium is toxic.
  • This article first appeared in H&H (24 June, 04)