| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* ARS, USDA, Subtropical Agricultural Research Station (STARS), Brooksville, FL 34601;
and
University of Georgia, Athens, 30602; and
and
University of Florida, Gainesville, 32611
4 Correspondence: 22271 Chinsegut Hill Rd. (phone: 352-796-3385; fax: 352-796-2930; E-mail: dgriley{at}mail.ifas.ufl.edu).
The objectives of this study were to assess the influence of sire on µ- and m-calpain activities, to evaluate the relationships of activities of these enzymes to other traits related to beef palatability, and to assess the influence of sire on the rate of tenderization (as measured by myofibril fragmentation index [MFI]) in Brahman longissimus muscle. Brahman calves (n = 87), sired by nine bulls, were born, weaned, fed, and slaughtered in central Florida. Traits evaluated were µ- and m-calpain activities and MFI after 1, 7, 14, and 21 d of aging. Other traits were analyzed to determine their associations with µ- and m-calpain activity and MFI, including calpastatin activity, percentage of raw and cooked lipids, Warner-Bratzler shear force (WBSF) values after 7, 14, and 21 d of aging, and sensory panel rating of tenderness, juiciness, and connective tissue amount after 14 d of aging. Data were analyzed using a model with sire, sex, year, and slaughter group (calves of the same sex slaughtered on the same date) as fixed effects, and adjusted to a constant adjusted 12th-rib fat thickness. Sire affected µ-calpain activity (P < 0.04), calpastatin activity (P < 0.01), d-14 MFI (P < 0.02), d-7 WBSF (P < 0.05), d-14 WBSF (P < 0.04), and sensory panel juiciness score (P < 0.01), but not (P < 0.75) m-calpain activity. Measures of tenderness and palatability were generally moderately to strongly correlated (both simple and residual correlations) with calpastatin and m-calpain activity. Myofibril fragmentation index residuals (adjusted for all model components except sire) after all aging periods were fitted using nonlinear regression to the exponential curve (MFIi = 
0 + 1 exp{2 ti} + 
i, where ti represents aging in days, 0 is ultimate MFI after aging, 1 is the difference between initial and ultimate MFI, 2 is the rate of increase in MFI, and i is the error term associated with the ith observation, assumed to be independent and identically distributed normally). Sires had different estimates and combinations of estimates, which were used to plot MFI change with time. These curves visually differed for sires and suggested that postmortem tenderization extent and rate differ as well. Use of a combination of these estimated parameters in a selection/carcass sorting program represents an alternative consideration for tenderization improvement programs.
Key Words: Brahman • Palatability • Postmortem Changes • Proteolysis • Tenderness
This article has been cited by other articles:
|
|
 |
|
  E. Casas, S. N. White, T. L. Wheeler, S. D. Shackelford, M. Koohmaraie, D. G. Riley, C. C. Chase Jr., D. D. Johnson, and T. P. L. Smith Effects of calpastatin and {micro}-calpain markers in beef cattle on tenderness traits J Anim Sci, March 1, 2006; 84(3): 520 - 525. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Casas, S. N. White, D. G. Riley, T. P. L. Smith, R. A. Brenneman, T. A. Olson, D. D. Johnson, S. W. Coleman, G. L. Bennett, and C. C. Chase Jr. Assessment of single nucleotide polymorphisms in genes residing on chromosomes 14 and 29 for association with carcass composition traits in Bos indicus cattle J Anim Sci, January 1, 2005; 83(1): 13 - 19. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
