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Title:Effects of ractopamine and muscle fiber number on swine growth performance, carcass traits, and meat quality
Author(s):Katzler, Louis W.
Director of Research:Killefer, John
Doctoral Committee Chair(s):Killefer, John
Doctoral Committee Member(s):McKeith, Floyd K.; Ellis, Michael; Carr, Scott N.
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
meat quality
birth weight
Abstract:The objective of this dissertation was to investigate the effects of ractopamine hydrochloride (RAC: Paylean®, ELANCO Animal Health, Greenfield, IN) on swine growth performance, carcass traits, meat quality and if its response is influenced by varying muscle fiber number and birth weight. The swine industry is under increasing pressure to maximize efficiency, profitability, and lean meat production. Advances in nutrition, genetics, and general livestock management have enabled producers to increase their efficiency. Increased efficiency is attained through shortening days to harvest (ADG), enhancing feed conversion (G:F), and increasing carcass leanness. One method to increase ADG, G:F, and carcass leanness is through the utilization of RAC. Ractopamine hydrochloride is an orally active β1 adrenergic agonist that is approved for use in the United States, and is incorporated into the pig’s finishing diet for the last 20.4 to 40.8 kg of BW gain. Numerous studies have demonstrated the efficacy of RAC in improving ADG, feed efficiency, carcass weight, dressing percentage, and its negligible effects on meat quality. In this group of studies it was also demonstrated that RAC (10 ppm) was able to increase ADG, G:F, and dressing percentage in pigs that were finished at heavier than normal weight of 147 kg. Ractopamine was also demonstrated to increase HCW, carcass cut yield, and lean cut yield linearly over durations of 7, 14, 21, 28, or 35 d (pooled response of 5.0 and 7.4 ppm). With both aforementioned studies, there were negligible effects on meat quality. Another way to increase productivity in swine production is through decreasing weight variation. Two factors that impact harvest weight variation is birth weight and muscle fiber number. It is commonly recognized that low birth weight correlates with decreased survivability and lower postnatal growth rates. Within this population of pigs that were investigated, muscle fiber number was not different between birth weight classes of light (0.9 kg), medium (1.2 kg), and heavy (1.5 kg). Muscle fiber diameter however, was increased 14.9 µm in the 5 ppm RAC light birth weight classification compared to the 0 ppm RAC light birth weight classification. When looking at the effects of muscle fiber number (tertile means of 1.3, 1.7, and 2.1 million fibers) on growth performance and meat quality, no trends or patterns were evident.
Issue Date:2010-05-19
Rights Information:Copyright 2010 Louis W. Kutzler
Date Available in IDEALS:2010-05-19
Date Deposited:May 2010

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