Hypoglycin A Concentrations in Seeds of Acer Pseudoplatanus Trees Growing on Atypical Myopathy‐Affected and Control Pastures

Background Hypoglycin A, found in seeds of A cer negundo , appears to cause seasonal pasture myopathy ( SPM ) in N orth A merica and is implicated in atypical myopathy ( AM ) in E urope. A cer negundo is uncommon in E urope. Thus, the potential source of hypoglycin A in E urope is unknown. Hypothesis and Objectives We hypothesized that seeds of A cer pseudoplatanus were the source of hypoglycin A in E urope. Our objective was to determine the concentration of hypoglycin A in seeds of A . pseudoplatanus trees located in pastures where previous cases of AM had occurred. Animals None. Methods University of Berne records were searched to retrospectively identify 6 farms with 10 AM cases and 11 suspected AM deaths between 2007 and 2011. During October 2012, A . pseudoplatanus seeds were collected from 2 to 6 trees per pasture on 6 AM farms (7 pastures) from trees in or close to 2 pastures on 2 control farms where AM had not been previously reported. Hypoglycin A in seeds was analyzed by GC – MS . Results A cer pseudoplatanus trees were identified on all AM pastures. Hypoglycin A was detected in all A . pseudoplatanus seeds in highly variable concentrations ranging from 0.04 to 2.81 μg/mg (mean 0.69) on AM farms and 0.10 to 9.12 μg/mg (mean 1.59) on control farms. Conclusion and Clinical Importance Preventing horses from grazing pastures containing A . pseudoplatanus seeds during late fall and early spring might be the best means to prevent AM .