RT Journal Article SR Electronic T1 Crackdown on factory farm drug use urged JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E23 OP E24 DO 10.1503/cmaj.109-4055 VO 184 IS 1 A1 Paul Christopher Webster YR 2012 UL http://www.cmaj.ca/content/184/1/E23.abstract