The latter part of June, 1941, one live and two dead pigs, weighing about thirty pounds each, were presented at the Diagnostic Laboratory, University of Minnesota, for the diagnosis of a herd problem.
Hoyt, H. H.
""Clay Pigeon" Poisoning in Swine,"
Iowa State University Veterinarian: Vol. 4
, Article 14.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol4/iss1/14