It's nice to treat your horse to special foods sometimes. However, there are a few things they probably shouldn't eat. What shouldn't you feed your horse? Here is a list of the foods that probably shouldn't be included in your horse's diet.
Fruit in Large Quantities
Many of us like to feed our horses apples as treats. But excessive amounts of fruit can become too much of a good thing. A belly full of apples or any other fruit can cause colic or other complications. You probably should not feed your horse more than one or two pieces of fruit. The danger is when horses have access to windfall fruit from a wild tree, or someone dumps a basket of spoiled apples over the fence thinking they’re giving the horse a "treat."
Lawn and Garden Clippings
Lawn and garden clippings can contain several hazards. Just-cut or semi-wilted plant material can be a problem in itself, even if it appears to contain nothing but grass.
Clippings can contain toxic plants and there are several common garden plants, like horse nettle, that fall into this category. Some weeds can also be toxic. Whatever gets sprayed onto lawns and gardens to control pests and weeds may be toxic too.
Because horses don’t have to graze and chew the material for themselves, they may bolt the food and fill up on it much faster. This can lead to choke and colic. The sugars in freshly cut or slightly wilted clippings can cause an imbalance in the horse’s gut, leading to laminitis. Put lawn and garden waste into your composter or manure pile, not over the fence into your horse’s pasture.
"Deadly Equines, The Shocking True Story of Meat-Eating & Murderous Horses" by CuChullaine O'Reilly, the Founder of the Long Riders' Guild, explores the fact that horses can and do eat meat (and some can appear to behave in quite a violent manner to get it). However, just because they can and do eat meat, does not mean that they should.
A horse may be trained to eat meat, or it may be driven to it by need. This doesn’t mean that a regular diet of meat in the long-term is a good thing. Your horse may like an occasional bite of your hamburger or tuna sandwich, and can eat it without harm. However, since we don’t know the long-term effects on most horses, a diet high in meat would be inadvisable (and expensive).
Horses have the teeth and digestive system of a highly specialized herbivore. Our horses will likely be healthiest eating the diet their digestive system has evolved to digest.
You may already know someone who gets uncomfortable after they eat cabbage, broccoli, kale, Brussels sprouts or other vegetables in the cabbage family. Your horse may feel the same type of discomfort after eating "gassy" vegetables like these. A few leaves or sprouts may not matter, but dumping the old plants over the fence probably isn’t a great idea.
Moldy or Dusty Hay
If good pasture is not available, good-quality hay is the next-best choice. However, never feed your horse dusty or moldy hay. To do so could lead to respiratory disease. It’s not okay to feed hay that’s only a bit dusty or has a bit of mold on it.
Many people may be surprised to learn that bran mashes are not recommended except as an occasional treat. Over-consumption of bran mashes can lead to mineral imbalances, so you might not want to offer them more than once a week, or preferably, even less frequently.
Eating alsike clover may cause a very nasty sunburn, sores in the mouth, and problems like colic, diarrhea, and big liver syndrome. Alsike clover is common in pastures. It can grow up to 30 inches/76 centimeters high and in addition to its clover-shaped leaves has a round flower head of pretty pink.
You can tell it apart from red clover because it doesn’t have the distinctive white "V" on the leaves that other clovers do. If your horse snaps up a few stalks of alsike clover occasionally, it’s probably okay, but prolonged consumption or a large amount at once may cause problems.
Cattle feed contains supplements that are good for cattle but are very toxic to horses. Drugs like rumensin are routinely added to cattle feed. These drugs can be deadly for horses. This is why it's a good idea to buy feed from mills that specialize exclusively in making horse feeds.
Silage and Haylage
Feeding haylage (sometimes called baleage) and silage to horses is more common in the UK and Europe than it is in North America. Feeding silage and haylage to horses can be tricky. There are some definite benefits to offering these forages to your horses, like a higher nutritional value and low levels of dust.
The manner in which the hay is cut and baled can increase the risk of botulism poisoning. Horses are very sensitive to the botulinum toxin and exposure to, or ingestion of the toxin can lead to paralysis and death. Because the hay is baled at a high moisture content and is wrapped in plastic, it is the ideal environment for toxin to grow. Soil carrying the botulinum toxin can be baled into the hay, where the bacteria may continue to grow.
The Ontario Ministry of Agriculture, Food, and Rural Affairs highlights both some advantages and disadvantages of feeding haylage and silage to horses. Eight types of botulinum toxins have been identified, but only three are known to affect horses. A vaccine is available for the most common type to affect horses - type B. Care must be taken to ensure uneaten silage or haylage is cleaned up. There is a possibility that frozen silage can lead to colic, and we don’t yet understand if there are long-term effects of feeding acidic (and treated or conditioned hay) fodder to horses.
Feeding Treats To Horses. Kentucky Equine Research.
Plants Toxic to Horses. Penn State University Extension.
Plumlee, K H. Pesticide toxicosis in the horse. The Veterinary clinics of North America. Equine practice vol. 17,3 (2001): 491-500, vii. doi:10.1016/s0749-0739(17)30047-0
Laminitis: Prevention & Treatment. American Association of Equine Practitioners.
Don’t Feed Your Horse Moldy Hay. University of Minnesota Extension.
Bran Mash. American Association of Equine Practitioners.
Alsike Clover Poisoning, Photosensitization Or Photodermatitis In Horses. Ontario Ministry of Agriculture Food and Rural Affairs.
Don’t Give Cattle Feeds To Horses! Kentucky Equine Research.
Ask the Expert: Feeding Baleage to Horses. University of Georgia Extension.
Hay, Haylage and Treated Hay for Horses. Ontario Ministry of Agriculture Food and Rural Affairs.