“…Some commonly used additives that improve growth rate or improve utilization of broiler feeds include bacitracin, in the form of either zinc bacitracin or bacitracin methylene disalicylate (Bird, 1968;Coates and Harrision, 1969;Creek and Schumaier, I960;Damron et al, 1975;Fernandez et al, 1973;Heuser and Norris, 1952;Matterson and Singsen, 1951;Stutz et al, 1983), and 3-nitro-4-hydroxyphenylarsonic acid [roxarsone (Abbott et al, 1954;Bird et al, 1949;Carlson et al, 1954;Frost, 1953;Libby et al, 1955;Milligan et al, 1955;Morehouse, 1949;Morehouse and Mayfield, 1946;Waldroup et al, 1984;West, 1956;Wharton and Fritz, 1953)]. Damron et al (1975) reported that there was no interaction between zinc bacitracin and roxarsone in regard to body weight gains or feed utilization by broilers. However, Fernandez et al (1973) reported that there was evidence of a beneficial additive effect between the two compounds.…”