Garlic - Is it Good for Horses?
By Eleanor Blazer
It's ironic that a plant touted as having "blood-cleansing" properties actually damages red blood cells.
Before feeding garlic to your horse, you should be aware of the danger.
Garlic contains several sulfur based compounds. When these compounds are broken down during digestion they form allyl methyl sulfide (AMS). AMS cannot be utilized by the body. It is picked up by the blood, carried to the lungs and skin and excreted.
If the concentration of AMS is high enough or present long enough, the red blood cells become damaged. The spleen recognizes the damaged cells and removes them. The horse eventually becomes anemic.
The question is, "How much garlic does it take to damage red blood cells?"
The answer is, "No one is sure."
The American Food and Drug Administration (FDA) classifies garlic as "generally recognized as safe" (GRAS) for the purposes it was intended. These purposes are providing taste, aroma or nutritive value.
Using garlic as a cure, disease preventative, a lessening of symptoms or as an oral insect repellent does not fall under the FDA's authority. These applications change the classification of garlic from "food" to "nutraceutical".
Nutraceuticals are believed to have preventative and curative health benefits. Most nutraceuticals have not undergone scientific study to confirm claims or rule out health problems they can create.
In a 2005 study conducted by Dr.'s Wendy Pearson, Herman Boermans, William Bettger, Brian McBride and Michael Lindinger two horses were fed freeze-dried garlic for 71 days. (Two other horses on a non-garlic diet were used as controls.) The garlic supplemented horses showed anemia at 0.2 grams per kilo of body weight (3.2 ounces for a 1,000 pound horse).
In a 1972 study published by the "Journal of the American Veterinary Medical Association" a study using onions (which also contains the sulfur based compounds) showed a horse that was fed four pounds of onion tops for four days developed anemia.
Granted the average horse owner is not going to feed this much garlic or onions to a horse. The question remains - "Do smaller amounts fed every day build up in the blood stream and cause undetected anemia?" Further studies need to be conducted to prove smaller amounts fed for a long period of time do not result in anemia.
The garlic source is also questioned. Some commercial garlic based supplements are diluted with other ingredients, which would decrease the concentration of garlic. Other products may have high concentrations of garlic. There are no regulations, so the buyer needs to exercise caution.
"Why feed garlic to horses?"
Many proponents of garlic say it cleans the blood. There is no scientific research that proves herbs clean the blood. The liver does an excellent job of keeping blood clean. It is more important to provide a balanced diet, offer fresh clean water at all times and keep horses from becoming obese. These simple steps help keep the liver healthy and functioning properly.
Garlic is also said to control intestinal worms. The amount needed to decrease internal parasites significantly would be toxic to the blood. Fecal egg counts have not shown garlic to be effective. Commercial dewormers are safer and proven effective.
Controlling flies and external pests is another use for which garlic is touted. The reasoning is the AMS excreted by the body will repel insects. Some horse owners say it works and others say it doesn't. I would be concerned with the amount needed to actually repel insects. If it's that strong in the blood, what's it doing to the cells?
Of course the number one reason for having garlic in the barn is confirmed by intense research done by authors and movies writers. If you live in an area plagued with vampires you should keep an abundant supply of fresh garlic bulbs on hand.
It's up to the horse owner to decide if she wants to try garlic. But my horse has enough problems without giving her something that could cause harm and has no scientific research to prove its value. Plus I like my barn to smell like a barn, not a restaurant!
Proper nutrition and management practices can prevent many problems associated with caring for horses. You can learn how to provide your horse with a better life-style by taking the online course "How to Feed for Maximum Performance" taught by Eleanor Richards Blazer.