Effect of efrotomycin on gain and feed efficiency for pigs from weaning until market weight.

Six studies involving 700 pigs were conducted in five separate swine research facilities to evaluate weight gain and efficiency of feed utilization in pigs fed the antibiotic efrotomycin. Pigs averaging 8.4 kg at the beginning of the studies were fed fortified corn-soybean meal diets that contained efrotomycin at 0, 2, 4, 8 or 16 ppm for an average of 120 d to market weight, about 92.1 kg. Pigs fed efrotomycin gained 5.9 to 8.9% faster (P less than .01) and were 1.7 to 4.0% more efficient (P less than .01) than those fed control diets. The improvement in growth rate was linear from 2 through 16 ppm, while feed efficiency (gain/feed) plateaued at 4 ppm efrotomycin. Treatment X study interactions were not significant for average daily gain or feed efficiency, showing that the response to efrotomycin was similar in each study. These studies indicate that efrotomycin is effective in improving gain and efficiency of feed utilization in swine from weaning until market weight.