Exercise intolerance / poor performance testing
If your horse isn't performing to the best of its ability, there may be an underlying problem that will need to be investigated by your vet. Exercise intolerance can have a number of causes and finding out what it is can be a lengthy process, but more often than not, treatment will be available to get your horse back on top form.
If your horse is performing poorly, it might be worth calling your vet so they can investigate any potential problems