UM Seeks Help in Seasonal Pasture Myopathy Research

Researchers at the University of Minnesota (UM) Equine Center are asking owners of horses suspected of having seasonal pasture myopathy (SPM) to submit information to help further the understanding of this pasture-associated muscle disorder of unknown cause.

Affected horses can either die acutely or show profuse sweating, muscle fasciculation (twitching), weakness, urine discoloration, reluctance to move, recumbency (inability to stand), difficulty breathing, and death after 12-72 hours. Since the etiology is unknown, no preventative treatment is currently available and affected horses can only be treated symptomatically.

"Our goal is to work with horse owners to identify which horses are at risk and find the best diagnostic test for this condition," lead researcher Stephanie Valberg, DVM, PhD, professor of large animal medicine and director of the Equine Center, said in a statement on the UM website.

Valberg and her team are asking horse owners across North America to carefully observe their horses this fall, as most cases occur during this time of the year. Should a horse display some or all of the aforementioned clinical signs, owners are asked to complete an online survey. A researcher will then contact the owner to discuss the probability of SPM as a cause of the affected horse's illness or death.

"If there is a positive correlation, we will need to contact your veterinarian for more information on clinical signs and test results," a statement on the UM website read. "In currently affected horses, we will need to obtain urine or serum samples for more advanced diagnostics. We will also have you complete a more detailed questionnaire about your pastures and their management as well as identify a helpful neighbor who does not have affected horses."

Thus far, the research has confirmed cases of SPM in several states, including Minnesota, Iowa, Wisconsin, North Carolina, and Texas.

For more information on the SPM research, owners are asked to email the UM Neuromuscular Diagnostic Laboratory at and type "SPM" in the subject line.

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