Semi-synthetic polyether ionophore antibiotic. Prepn: A. C. Goudie, N. D. A. Walshe, EP 255335; eidem, US 4804680 (1988, 1989 both to Pfizer). LC determn in poultry liver: J. F. Ericson et al., J. AOAC Int. 77, 577 (1994). Metabolism and tissue residue studies in broiler chickens: M. J. Lynch et al., ACS Symp. Ser. 503, 49-69 (1992). Anticoccidial effects in chickens: M. E. McKenzie et al., Poult. Sci. 72, 2052 (1993); N. B. Logan et al., ibid. 2058.