• Journal of Animal Science and Technology
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• v.52 no.5
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• pp.427-434
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• 2010

This study was conducted to investigate the growth performance and meat quality improvement according to castration, optimal feeding management and ruminally protected amino acid-enriched fatty acid (RPAAFA) for the unselected Hanwoo bulls in the performance test. Bulls were castrated at approximately 14 months of age. Sixteen Hanwoo steers, 15 months of age and weighing $412.9{\pm}24.9kg$, were distributed into 2 groups. Steers were fed a basal diet supplemented with RPAAFA at 0 g (control) or 100 g (treatment), respectively for 12 months. Steers were slaughtered at 27 months of age. Average daily gain for treatment tended to be higher (p=0.10) than that of control, whereas feed conversion ratio tended to be lower (p=0.07) in treatment than in control. The supplementation of RPAAFA did not affect rib eye area, back fat thickness, meat color, fat color, texture and maturity. The appearance rates of yield 'A' grade and high quality grade ($1^{++}$, $1^+$ and 1) were higher in treatment than in control. The content of moisture, fat, protein and ash in longissimus muscles were similar between control and treatment. The supplementation of RPAAFA did not affect water-holding capacity, oxidation and reduction potential, myoglobin and fatty acid contents in longissimus muscles. Thus, present results indicate that castration, optimal feeding management and RPAAFA may be recommended for improving growth performance and quality grade of the unselected Hanwoo bulls in the performance test.

• Journal of Animal Science and Technology
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• v.52 no.6
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• pp.499-504
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• 2010

This study was conducted to determine the effects of ruminally protected amino acid-enriched fatty acids (RPAAFA) on body weight gain, feed intake and carcass characteristics of fattening Hanwoo cows. Twenty eight Hanwoo cows, $6.0{\pm}1.7$ years old and weighing an average of $463.2{\pm}77.6\;kg$, were used for 4 months. Animals were fed a basal diet supplemented with RPAAFA at 0 g (control) and 100 g (treatment), respectively. Average daily gain, dry matter intake and feed conversion ratio were not different among the control and treatment. The supplementation of RPAAFA did not affect carcass weight and rib eye areas. Quality grade score ($1^{++}$, $1^+$ and 1) for treatment was higher in RPAAFA supplemented group compared with the control, whereas no differences appeared in meat color, fat color, texture and maturity. Thus present results indicate that supplementation of RPAAFA may be recommended for producing high quality beef from fattening Hanwoo cows.