Use of Antibiotics and Roxarsone in Broiler Chickens in the USA: Analysis for The Years 1995 to 2000

This is the authors' abstract. We don't add key points for this paper.

In 1995, an antibiotic (ANT) was used in starter, grower, and withdrawal (WD) feeds by 94.3, 98.2, and 75.1% of broiler production units, but by 2000, ANT use had declined to 64.8, 66.9, and 48.1% respectively. Roxarsone (ROX) was used in the starter and grower feeds by 69.8 and 73.9% of production units. Bacitracin (BAC) was used more frequently than other antibiotics in the starter and grower feed. Virginiamycin (VIR) was used most frequently in the WD feed. Most units (69.4%) reported use of two different antibiotics. The use of programs comprising two ANT decreased, whereas programs with a single ANT increased during the period of study. A combination of ionophore (ION) + ROX + ANT was employed most frequently in the starter and grower feeds, whereas an ANT alone was used most frequently in the WD ration. The use of ION + ROX + ANT declined from 1995 to 2000, but use of ION + ROX increased. There were no significant differences in calorie conversion whether plants used ION + ROX + ANT, ION + ROX, or ION + ANT. The number of days to rear birds to 2.27 kg was significantly greater for production units using ION + ROX. Mortality was lower for units that used ION + ROX + ANT and ION + ROX than for those that used ION + ANT. Production units that used ION + ANT were more likely to rear birds to a weight greater than 2.5 kg than to 2.0 to 2.5 kg. Units in the South and Central states were more likely to use an ION + ROX than those in the Northeast and Atlantic states, whereas for ION + ROX + ANT the reverse was the case. The cost of medicating with ION + ROX + ANT decreased from 1995 to 1998.