‘You should always withhold feed before exercise’
‘You should never feed a hot horse after exercise – let them cool down first’
‘You need to withhold feed for performance horses for at least 12 h before a race or competition’
‘You need to take your horse off the grass for at least an hour before you ride’
These are just a few opinions about feeding horses before and after exercise, and there are many more. In reality, how to feed around exercise depends on the horse, the exercise they are about to perform, and the feed involved. Fortunately, there is some research in this area, which can help us to make more informed decisions about how and when to feed around exercise.
For leisure horses or light to moderate exercise, there is no need to remove a horse from grass if they are on ad lib feeding. Such a horse would have a normal, ‘trickle’ intake of forage and can exercise at low to moderate levels without any problem. The same goes for access to a haynet or a small, fibre-based feed. Leaving no time between these and light to moderate work is not a problem. Horses hold feed in their stomach for long periods (their stomachs are never empty if fed correctly) so it is acceptable for them to exercise in this state. In fact, it is unhealthy for horses to exercise after a fast because there is likely to be more acid in their stomachs than normal, which will splash as they exercise.
Large meals of anything, especially for a horse who has been fasted or feed-restricted immediately beforehand, is not recommended before exercise because fluid from the body shifts into the digestive tract and therefore lowers cirulcating blood volume and availability of fluid for sweating.
Large, grain-based meals are not recommended prior to exercise. These have more consequence on the horse’s physiology during exercise, causing shifts in hormones including insulin and in blood distribution. Large grain-based meals fed within 3 hours pre-competition might impair performance due to the insulin response – the body needs to be in a ‘breaking down’ or catabolic phase during exercise, not a nutrient storage ‘building up’ anabolic phase.
Horses with or prone to gastric ulcers should actively be fed a small amount of fibre-based feed and ideally alfalfa before exercise, to help buffer stomach acid and limit acid-splashing.
Horses should be cooled down thoroughly after exercise, and this is part of a good management regime. It will do them no harm to have a little fibre-based feed when still hot, and endurance horses are actually trained to eat ‘on the run’ in order to keep their digestive tracts healthy and replenish their nutrient delivery on very long rides. Horses should not be fed large grain-based meals before they have cooled down thoroughly after exercise i.e. their respiratory and heart rates have returned to resting rates.
The consumption of small meals of forage before exercise of any level, including racing, is recommended to support good stomach health without having an adverse effect on performance or general health. Horses kept out at grass all the time – i.e. not those whom are turned out for restricted periods, who might eat a large amount of grass in a short period – can be ridden straight away, providing sufficient warm up is carried out before fast work. Large grain-based meals should not be fed within 3 hours of moderate or more intense exercise, and are generally contraindicated for good health regardless of performance.