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
Recent rulings by the Food and Drug Administration make it more imperative than ever that practitioners use, sell, and recommend proper insecticides for the control of ectoparasites. Very few of the commonly used insecticides have a tolerance established by the FDA in meat and dairy products.
Raum, Earle S.
"Large Animal Ectoparasite Control,"
Iowa State University Veterinarian: Vol. 22
, Article 6.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol22/iss2/6