Authors : J.C. Woodworth , M.D. Tokach , J.L. Nelssen , R.D. Goodband , P.R.O. Quinn and T.M. Fakler
Abstract: Two trials were conducted to determine the effects of diet complexity, feed-grade antibiotic and zinc (Zn) source on weanling pig growth performance. In Exp. 1, 320 pigs (initially 4.42 ? 0.09 kg and 14 d of age) were allotted in a 2?2?2 factorial with main effects of diet complexity (simple or complex); added zinc oxide (ZnO; none or 3,000 ppm Zn from d 0 to 10 then 2,000 ppm from d 10 to 20); and feed-grade antibiotic (none or 55 mg neoterramycin/kg of diet). Experimental diets were fed from d 0 to 20 after weaning and then a common diet that contained no ZnO (other than provided in the trace mineral premix) or antibiotic was fed to all pigs from d 20 to 27. From d 0 to 10, a three-way interaction was observed (p<0.02) for ADG, which appeared to be a result of an additive response to both ZnO and the antibiotic in simple diets, whereas in complex diets, either ZnO or antibiotic was equally effective in improving ADG. Pigs fed complex diets had improved (p<0.05) ADFI throughout the trial and ADG was increased (p<0.05) in all phases except d 20 to 27. Pigs fed diets containing ZnO had greater (p<0.05) ADG from d 5 to 10, 0 to 20 and 0 to 27 and greater (p<0.05) ADFI from d 5 to 10, 0 to 10 and 0 to 20 compared to pigs fed no added Zn. The feed-grade antibiotic increased (p<0.05) ADG from d 10 to 20, 0 to 20 and 0 to 27. In Exp. 2, 288 pigs (initially 5.59 ? 0.12 kg and 18 d of age) were allotted in a 2?3 factorial with main effects of antibiotic (none or 55 mg carbadox/kg of diet) and Zn source (none, 250 ppm Zn from a Zn amino acid complex (ZnAA), or 3,000 ppm Zn from ZnO). From d 0 to 14, pigs fed diets containing ZnO had greater (p<0.01) ADG than pigs fed no added Zn and those fed ZnAA were intermediate. From d 14 to 27, added Zn did not affect ADG, but ADFI tended to increase (p<0.07) with added ZnO. Feed-grade antibiotic had no effect from d 0 to 14 but tended to increase (p<0.08) ADG and ADFI from d 14 to 27. These data suggest that diet complexity, added Zn and feed-rade antibiotic influence growth performance of weanling pigs. The diet complexity and Zn responses were observed primarily during the first 10 to 14 d of the studies and the antibiotic response was predominantly observed from d 10 or 14 to the end of the experiments. From d 0 to 14, pigs fed ZnO had greater (p=0.05) ADG than ZnAA, but both Zn sources increased (p<0.01 and 0.07, respectively) ADG compared with pigs fed no added Zn.
J.C. Woodworth , M.D. Tokach , J.L. Nelssen , R.D. Goodband , P.R.O. Quinn and T.M. Fakler , 2005. Interactive Effects of Diet Complexity, Zinc Source and Feed-grade Antibiotics on Weanling Pig Growth Performance . Journal of Animal and Veterinary Advances, 4: 688-693.