THE EFFECT OF RACTOPAMINE HYDROCHLORIDE ON THE CARCASS CUTTING YIELDS OF FINISHING SWINE

This study was designed to evaluate growth performance, carcass cutting yield, and processing characteristics of boneless hams and bellies from finishing pigs fed diets containing 0, 5, 10, or 20 ppm of the phenethanolamine ractopamine hydrochloride (RAC). Sixty pigs were blocked by starting weight and randomly assigned to pens (four pigs/pen) within each of three blocks. Treatments were then randomly assigned to the pens to total six pens of the 0-ppm level and three pens each at the 5-, 10-, and 20-ppm RAC levels. Weight gain and feed consumption were monitored and animals were slaughtered by weight block after approximately 48 d on trial. Slaughter weight, ADG, and feed/gain were improved (P < .05) for RAC treatments. Dressing percentage was higher and increased linearly (P < .05) for RAC treatments. Carcass weight, length, leaf fat weight, backfat thickness, loin eye area, and color, marbling, and firmness of the longissimus were evaluated. The RAC-treated carcasses were heavier (P < .05) and loin eye area increased linearly (P < .05). One side of each carcass was fabricated using National Association of Meat Purveyors specifications. Trimmed hams and loins from the RAC treatments were heavier (P < .05) than those from control animals. No differences (P > .05) in carcass cutting yield (percentage of trimmed primal cuts) were observed between treatments. However, trimmed hams and loins from the 20-ppm RAC treatment represented a greater (P < .05) percentage of carcass weight than did those from control animals. Ractopamine did not affect raw belly or bacon characteristics (P < .05). These results indicate that RAC improved the growth and performance characteristics, increased the yield of ham and loin from the carcass, and did not adversely affect belly thickness or processing characteristics of bacon.