Penicillin G in Calves Choose route: IM | IV | PO Intramuscular (IM) Reference for this graph: Bengsston 1989, Luthman 1986, Ziv 1982 Intravenous (IV) Reference for this graph: Guard 1988, Luthman 1986, Musser 2001 Oral (PO) Reference for this graph: Musser 2001 CLSI Breakpoint Information