Horses with Pica Lack Trace Elements, Researchers Report

A recent study found that horses with pica--a propensity for consuming non-food items--have lower iron and copper blood levels than horses who restricted themselves to food items only. According to researchers from Turkey, "prophylactic use of iron and copper supplements in horses may be beneficial to prevent pica."

Horses with pica can lick or mouth foreign substances or, in some cases, actually ingest the materials. Some of the more common forms of pica in horses include chewing bones (osteophagia), ingesting feces (coprophagia), chewing and eating wood (lignophagia), and eating soil or sand (geophagia). Pica is problematic as it can cause colic and tissue damage due to migrating foreign bodies.

While the underlying cause of pica remains unknown, a multitude of hypothesis exist such as underlying health problems, dietary deficiencies, and nervous system disturbances, among others.

Control of pica has traditionally involved providing salt and mineral supplements, feeding fresh grass, greens, and carrots, providing higher levels of hay or long stem forage, feeding at the same time every day, regular deworming, feed analysis, physical examination and routine blood work performed by a veterinarian, and cross-tying horses in their stalls to prevent the untoward behavior.

To obtain more information on pica, the Turkish research group measured blood cell counts, blood biochemistry, and circulating trace element concentrations in horses with (n=15) and without (n=15) pica. The only values that were significantly different between the two groups were the iron, copper, and the copper to zinc ratio.

According to Carey Williams, PhD, equine extension specialist and associate director of the Rutgers University Equine Science Center, who commented on the study, "There is the occasion where pica can also be due to boredom, which is why it is a good idea to start with providing extra grass hay to see if that will solve the problem. If that doesn't work, then it is a good idea to check with your veterinarian or nutritionist to see if any dietary changes are necessary, especially if supplementation may be necessary."

Williams emphasized a need for caution when supplementing.

"Excess supplementation of trace minerals is not good. As always, make any changes to the diet slowly. It is also important to note that blood levels of iron do not necessarily reflect what is in or should be in the diet; however blood levels of copper may directly reflect any dietary excesses or deficiencies. Therefore caution needs to be exhibited when deciphering this study's results," she concluded.

The study, "Changes in serum mineral concentrations, biochemical and hematological parameters in horses with pica," will be published in an upcoming edition of the journal Biological Trace Element Research. The abstract is available on PubMed.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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