Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
There have been numerous reports in the past few years of ulcerative conditions of unknown etiology involving either the oral cavity or perineal area of feeder cattle. The lesions seem to develop primarily as erosive or nectrotic areas on the tongue or vulva and may heal rapidly or secondary bacterial invasion may occur with subsequent extension of the lesion into surrounding tissues. This report deals with a condition observed in feeder cattle where ulcerative lesions develop on both the muzzle and in the perineal area.
Tyler, D. E. and van der Maaten, M. J.
"An Ulcerative Condition Involving the Muzzle and Perineal Area of Feeder Cattle,"
Iowa State University Veterinarian: Vol. 25
, Article 7.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol25/iss3/7