2011 Annual Report
2. Develop strategies to optimize meat quality and composition traits of meat. a. Develop strategies to improve the value of underutilized muscles. b. Validate that the µ-calpain and calpastatin tenderness markers that were developed and have been verified in structured research populations will be efficacious when applied to the diverse genetics, management systems, and harvesting conditions that occur in the U.S. beef industry. c. Determine the level of differences among lamb breeds in biochemical traits controlling variation in tenderness and develop strategies to exploit these differences to optimize lamb quality and carcass composition.
Trials indicated that pork loin chops from carcasses produced in plants utilizing rapid chilling systems were less tender than those from carcasses produced in plants utilizing conventional chilling methods. Pigs from a common source were transported equal distances to three processing plants differing in the chilling methods. Vacuum-packaged loins were aged and tenderness was measured objectively with slice shear force at 15 days after harvest, which is approximately the average time between harvest and retail consumption of loin chops. Chops from loins produced in the plant using rapid chilling systems were tougher than those from loins produced in the plant using conventional chilling systems.
Furthermore, work on the contribution of animal effects on lean color stability determined that lean color stability measurements were highly repeatable. Duplicate top loin steaks from each of 100 beef carcasses were placed in simulated retail display during which lean color change was measured. Color change was highly repeatable indicating that simulated retail display data are suitable for use in genomic studies. Further work determined that postmortem aging has a profound detrimental effect on retail color life. In this experiment, top loin steaks were removed from 100 beef carcasses after grading and placed in simulated retail display. The strip loin was then obtained after fabrication and aged for 14 days before a second steak was placed in simulated retail display. The remaining portion of each loin was repackaged and aged until 35 days postmortem before a third steak was placed in simulated retail display. The rate and extent of discoloration during simulated retail display differed greatly between aging times. However, discoloration was highly correlated across aging times. Thus, findings from display studies utilizing steaks produced under one set of aging parameters can be applied to steaks produced under other parameters. One important implication of this work is that retail color stability measurements can be readily incorporated into our current data collection protocols for genomic studies without increasing costs or decreasing sample numbers.
King, D.A., Shackelford, S.D., Rodriguez, A.B., Wheeler, T.L. 2011. Effect of time of measurement on the relationship between metmyoglobin reducing activity and oxygen consumption to instrumental measures of beef longissimus color stability. Meat Science. 87(1):26-32.
King, D.A., Shackelford, S.D., Wheeler, T.L. 2011. Relative contributions of animal and muscle effects to variation in beef lean color stability. Journal of Animal Science. 89:1434-1451.
Lindholm-Perry, A.K., Rohrer, G.A., Holl, J.W., Shackelford, S.D., Wheeler, T.L., Koohmaraie, M., Nonneman, D.J. 2009. Relationships among calpastatin single nucleotide polymorphisms, calpastatin expression and tenderness in pork longissimus. Animal Genetics. 40(5):713-721.
Zhang, S., Knight, T.J., Reecy, J.M., Wheeler, T.L., Shackelford, S.D., Cundiff, L.V., Beitz, D.C. 2009. Association of polymorphisms in the promoter I of bovine acetyl-CoA carboxylase-alpha gene with beef fatty acid composition. Animal Genetics. 41:417-420.
Wheeler, T.L., Cundiff, L.V., Shackelford, S.D., Koohmaraie, M. 2010. Characterization of biological types of cattle (Cycle VIII): carcass, yield, and longissimus palatability traits. Journal of Animal Science. 88:3070-3083.
Everts, A.K., Wulf, D.M., Wheeler, T.L., Everts, A.J., Weaver, A.D., Daniel, J.A. 2010. Enhancement technology improves palatability of normal and callipyge lamb. Journal of Animal Science. 88:4026-4036.
Garcia, M.D., Matukumalli, L., Wheeler, T.L., Shackelford, S.D., Smith, T.P., Casas, E. 2010. Markers on bovine chromosome 20 associated with carcass quality and composition traits and incidence of contracting infectious bovine keratoconjunctivitis. Animal Biotechnology. 21(3):188-202.
Lindholm-Perry, A.K., Rohrer, G.A., Kuehn, L.A., Keele, J.W., Holl, J.W., Shackelford, S.D., Wheeler, T.L., Nonneman, D.J. 2010. Genomic regions associated with kyphosis in swine. BMC Genetics. 11:112.