Equines are designed to eat a plantbased diet – period. As “obligate herbivores” their teeth and digestive systems cannot handle meat and even some fruits and vegetables, although we’ve all heard stories of ponies that loved to wash down pizza with a Dr. Pepper. Here are some “people” foods you should avoid feeding your horse:
Coffee, tea and cola contain the stimulant caffeine (trimethylxanthine) which can cause an irregular heart rhythm.
Also toxic to cats and dogs, the theobromine in chocolate can cause severe colic, seizures, metabolic derangements and internal bleeding in horses.
(Note: Although they are stimulants, the FEI has decided that the resources required to process methylxanthine cases, which include caffeine- and theobromine-positive tests, are not proportional to their perceived threat to the sport, and has instead put caffeine on a ‘monitoring’ list.)
Garlic and onions:
These members of the allium family, which also includes leeks, scallions, shallots and chives, contains the chemical N-propyl disulfide which can destroy red blood cells and result in anaemia. While garlic is a popular equine supplement, moderation is the key.
The tomato is a member of the toxic Solanaceae plant family, which includes deadly nightshade. The leafy green portions of the tomato plants contain atropine, which can cause colic by slowing gut function. Hyoscyamine in tomatoes decreases saliva production and intestinal motility, increases the heart rate and causes constipation and/or hemorrhagic diarrhea. Other members of this family, such as chili peppers and eggplant, should also be avoided.
Fruit seeds and pits:
Some fruits – such as apples and apricots – have pits or seeds which contain cyanide compounds, which are toxic in extremely large quantities. Large pits can cause choke, so it’s best to remove them before offering your horse fruit such as peaches or nectarines.
Dog and cat kibble:
Dry kibble containing grain products may be tempting to horses and seem harmless enough, but it also contains meat by products and as such is not suitable for equine consumption.
The major dangers with potatoes are 1) if the potato is green or rotten, the chemical composition can cause toxicosis in all animals, including horses; or 2) if the potato is whole, it can become lodged in the windpipe and result in choke. (This warning applies to any large, round, firm fruits or vegetables, even apples, which should be cut into pieces before offering.)
Some house plants are dangerous to horses and can result in diarrhea, renal failure, liver damage, colic, and even death, depending on the species. While you wouldn’t intentionally feed rhododendrons or daffodil bulbs to your horses, be careful they do not have access to live or discarded plants. (For a complete list of plants poisonous to horses, check here. )