ARE HORSES HAZARDOUS TO CONSERVATION LAND? OUR EXPERTS SET THE RECORD STRAIGHT
Trail riders frequently need to rise to the defense of their equine partners. This
article, presented by the Equine Land Conservation Resource and reprinted here by permission, dispels many mistaken beliefs about how horses impact the land.
MYTH: Horses introduce non-native plants and prop- agate nuisance weed seeds along trails.
FACT: According to current research, horses do not introduce
non-native plants along trails. Dr. Stith T. Gower of the Department of Forest Ecology and Management at the University of Wisconsin, Madison concluded that the ratio of non-native plants to native spe- cies on trails “did not differ between trails open and closed to horses” at three study sites. Gower’s finding is consistent with those of Mary Benninger-Truax,
et al, who found no documentation that horses are a major source of exotic species. She determined that horses that were not allowed to graze in an area with exotics and had controlled diets did not spread weed seed along the trails.
MYTH: Horses can transmit foot-and-mouth disease and Mad Cow disease.
FACT: Foot-and-mouth disease (FME) affects only cloven-footed
ruminants—such as sheep, catle, and goats. Neither of these diseases affects horses. Te US has had no cases of FME since 1929. Horses that are imported to the US from countries with outbreaks of FME are quarantined for three days and sponged with vinegar to kill any potential virus that may have been transported on their hooves. During epidemics abroad, such as the one that occurred in 2001, the federal government may also prohibit imports of horses and all other animals from countries where FME cases exist. Te US Department of Agriculture reported one case of Bovine
Spongiform Encephalopathy (BSE), commonly called Mad Cow Dis- ease, in 2003. Tis single case occurred in a Washington state dairy cow born in Canada prior to the US prohibitions on risky feeding behaviors. Tere is no evidence that horses were in any way involved in this case. BSE is currently believed to occur by feeding infected ruminant protein to other ruminants; this practice is prohibited in the US.
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MYTH: Horses spread Eastern Equine Encephalitis. FACT: Contact with horses does not pose a risk of con-
tracting Eastern equine encephalitis (EEE) to humans or oth- er animals. While EEE is a viral disease that can af fect hu- mans, horses, and birds, horses are “dead-end” hosts for the virus. In other words, horses can get EEE from an infected mos- quito, but they cannot infect other animals, humans, or mosquitoes. EEE is transmited to humans only through mosquito bites. Tere are approximately five cases of human EEE infection per year in the US.
MYTH: Horses spread E. coli, Salmonella, Cryptospo- ridium, Giardia and other waterborne diseases. FACT:According to Johnson et al., scientific studies confirm that
adult horse intestines do not contain significant quantities of E. coli 0157:H7, Salmonella, Cryptosporidium, or Giardia, which are the or- ganisms of most concern in the waterborne spread of disease. In other words, horses are not responsible for the spread of waterborne diseases.
MYTH: Horses emit greenhouse gases. FACT:Horses are not a significant source of methane gas, the gas of
concern in greenhouse/global warming issues. “Te primary source of methane release in livestock production is ruminant animals,” accord- ing to the ARS Air Quality National program (as cited by the USDA Agricultural Research Service).
MYTH: Horseback riding on trails causes erosion. FACT: According to Professor Gordon E. Brown Jr. of Stanford
University’s School of Earth Sciences, the primary causes of erosion are natural and far surpass any impact of trail use by horses. In a five-year study, Summer concluded that horse traffic was not
the dominant process causing erosion on trails. Trail degradation was a function of landform, climatic and catastrophic events and geomorphic
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