Effect of Ractopamine Hydrochloride on Growth and Carcass Characteristics of Lightweight Swine

Mark A. Frenzel, Randy M. Harp, Barry D. Lambert, Joe M. Cadle, Leslie L. Garcia


This study was conducted by using 65 pigs to measure the effects of feeding ractopamine hydrochloride (RAC) on growth and carcass characteristics of lightweight swine. Beginning weights averaged 68.23 kg. RAC was included in the diet at 0, 5, or 10 ppm for 25 days until an average end weight of 92 kg was achieved. Loin eye area, trimness (backfat measurements), and pork muscle quality factors of carcasses were evaluated 24 hours post-harvest at a commercial processing facility by trained personnel. No differences (P>0.05) were found between treatment groups for average daily gain (ADG) or feed:gain ratio. Groups fed 5 ppm RAC had lower weight loss from drift (P<0.05). No differences (P>0.05) between treatment groups were found for dressing percent, carcass length, first rib fat thickness, tenth rib fat thickness, or loin eye area. Last rib fat thickness and last lumbar fat thickness were significantly lower (P<0.05) for the two groups fed RAC. Firmness, color, and marbling were not affected by treatment group (P>0.05). These results suggest that feeding RAC to lightweight swine can reduce last rib fat while not impacting growth or other carcass traits.


Ractopamine; pork; carcass traits; growth; fat thickness; muscling

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