Effects of in-feed antimicrobial alternatives and antimicrobials on nursery pig performance and weight variation

Abstract

Objectives: To compare the effects of several antimicrobial alternatives and in-feed antimicrobials on nursery pig performance. Methods: In Experiment One, 720 nursery pigs were used to evaluate feeding three yeast products (LactoSacc, Alltech, Nicholasville, Kentucky; Biomate Yeast Plus, Chr Hansen BioSystems, Milwaukee, Wisconsin; BioSaf, Saf Agri, Minneapolis, Minnesota); three antimicrobial products containing bacteria (Probios and Bio-Plus 2B, Chr Hansen BioSystems) or oligosaccharides (Bio-Mos, Alltech); and the antimicrobial carbadox (Phibro Animal Health, Fairfield, New Jersey). In Experiment Two, 320 nursery pigs were used to evaluate feeding LactoSacc, Bio-Plus 2B, Bio-Mos, and carbadox in an on-farm trial. In Experiment Three, 320 nursery pigs (same commercial herd as in Experiment Two) were used to evaluate feeding carbadox, a combination of tiamulin (Boehringer Ingelheim Vetmedica, St Joseph, Missouri) and chlortetracycline (Alpharma, Fort Lee, New Jersey), a combination of neomycin and oxytetracycline (Phibro Animal Health), and Bio-Mos. Results: In Experiment One, in pigs fed the carbadox diet, ADG was greater (P < .05) than in pigs fed all other diets, and feed:gain was better (P < .05) than in pigs fed the control diet or the Probios diet. In Experiment Two, performance did not differ among treatment groups and controis. In Experiment Three, pigs fed the tiamulin-chlortetracycline and neomycinoxytetracycline diets had greater ADG and average daily feed intake compared with control pigs (P < .05). There were no differences in growth performance among control pigs and those fed the carbadox or Bio-Mos diets. Implication: The antimicrobial alternatives evaluated did not enhance growth performance.