Influence of antimicrobial sequence in the nursery on pig performance and economic return

A total of 1,008 pigs (11.9 lb and 19 d of age) were used in a 42-d experiment to determine the influence of antibiotic regimen on growth performance and economic return. From d 0 to 10, pigs were fed diets containing either no antibiotic or Denagard at 35 g/ton and chlortetracycline at 400 g/ton (Denagard/CTC). From d 10 to 21, diets contained no medication, Denagard/CTC, Mecadox at 25 g/ton and Oxytetracycline at 400 g/ton, or Mecadox at 50 g/ton. From d 21 to 42, diets contained either no medication or Denagard/CTC. Adding Denagard/CTC to the diet from d 0 to 10 improved (P 0.49). Overall, MOFC was increased when antibiotics were added to the diet from d 0 to 10 and d 10 to 21 when gain was valued at $0.50 or $1.00/lb and tended to increase (P < 0.06) when Denagard/CTC was added to the diet from d 21 to 42 when the extra gain was valued at $1.00/lb. These results demonstrate that adding antibiotics to the nursery diet improved pig performance and economical return on this commercial farm.