The term 'bolt' can be used in two senses with a horse. One sense is 'to run away', the other is 'to eat dangerously fast'. This article considers the second issue, namely horses eating their food excessively fast, which is sometimes expressed as 'horse bolting' but is more clearly expressed with the term 'bolting food' (e.g. my horse bolts its feed).
The main issue with horses bolting their feed is that it can lead to choke, a dangerous condition where the food becomes stuck in the throat and creates a blockage which prevents the horse from eating or drinking. Choke can also lead to damage to the lungs due to food or liquids over-spilling from the blockage into the trachea and thereby into the lungs. For details on this condition and its treatment, see horse choke.
A secondary issue is that insufficiently chewed food is more difficult to digest and may simply pass through the horse. Although this is inefficient (e.g. up to half the grain fed to a horse may be lost in this manner), provided the horse has enough to eat it is normally not a health issue.
Not all horses bolt their food. With horses that bolt, it is normally only concentrated food (e.g. grains or hay pellets) which are bolted, whereas grass and hay are not bolted.
Causes and Prevention
Bolting has two causes. One is simple gluttony; just as some people are food gluttons who eat as much as they can and as quickly as they can, so do some horses. The second cause is fear that another horse will take the food if it is not quickly eaten. For this reason, bolting is much more common among horses which are fed together.
If a horse bolts its feed, one should consider feeding it separate from other horses. Note that as bolting normally occurs with grain rather than hay, the separate feeding only need apply to grain and not to straw.
If a horse still bolts when fed separately, additional approaches are:
- Hay before Grain. When horses are put in their boxes for the night, if they have some time to eat their hay before being fed grain, they may be less hungry and consequently less likely to gobble their grain down.
- Obstacles. Placing a few large stones in the feeding bucket or trough will restrict the horses access to the grain. The stones should be big enough that the horse cannot swallow them, should be round and smooth (so the horse cannot injure its tongue or nose on them) and should be chemical free. They should be small enough that the horse can easily move them around with its nose to access the grain. This allows the horse to eat its feed but the physical process of moving the stones to access the grain will greatly slow down the rate of eating. Some people use mineral stones or salt licks instead, although personally I consider that this risks the horse ingesting more salt and minerals than it requires. When using obstacles to prevent bolting, one needs to ensure that all the grain is eventually eaten or that the feed trough is cleaned daily to prevent left over feed from going sour.
- Smaller feeds. If all else fails, instead of providing feed daily, provide multiple smaller amounts through the day. This way, even if the horse continues to bolt its food, due to the smaller amounts it is much less likely to choke.
As choke is the main issue associated with bolting, if your horse continues to have this problem, see Horse Choke for further advice on how to prevent this condition.