|Chase, Chadwick - Chad|
Submitted to: Florida Cattleman
Publication Type: Trade Journal
Publication Acceptance Date: 12/7/2005
Publication Date: 1/7/2006
Citation: Riley, D.G., Chase, C.C., Johnson, D.D., Olson, T.A. 2006. Brahman beef tenderness research. Florida Cattleman and Livestock Journal. 70(4):42-43. 2006.
Technical Abstract: A research report from the late 1980s was among the first prominent studies to associate poor beef tenderness with the Brahman breed. Without doubt, this and subsequent similar reports have been used in part as justification for price discrimination against Brahman cattle at various points in the beef production system. Investigation of tenderness improvement in Brahman cattle became an important topic, and in the mid 1990s an experiment was planned and conducted at the Subtropical Agricultural Research Station to this end. Experimental Procedures This experiment was conducted by mating 27 Brahman bulls to the Brahman cow herd at Brooksville over seven years. Most of the bulls used in this study were Florida Brahman and loaned to the station for this purpose. After weaning, steers and heifers were fed as calves in the station feedlot. When a pen (about 12 or 13 calves) averaged ½ inch of backfat, they were slaughtered at Central Packing in Center Hill. University of Florida (UF) and STARS personnel collected a variety of data after slaughter. Although the purpose of this experiment was to evaluate all beef quality, quantity, and palatability traits, tenderness was of special interest and consequently was measured in multiple ways. Warner-Bratzler shear force (force in lb required to pull a dull blade through a ½ inch core of meat) was measured after 7, 14, and 21 days of refrigerated aging. A trained UF sensory panel evaluated different aspects of tenderness after 14 days of aging. Physical measurements of tenderness (fragmentation of muscle fibers) were measured on a subset of carcasses after 1, 7, 14, and 21 days of aging. Selection for Tenderness? Estimates of heritability for tenderness and related traits from these data ranged from 0.06 to 0.14. Heritability is the amount of genetic control of a given trait; these represent proportions of the total variability for each trait. These estimates are quite low; note that heritability estimates for weight traits in cattle generally range from 0.25 to 0.45. It is easy to select for weight at given ages; the lower estimates of heritability for tenderness traits mean that it would be more difficult to select for improvement and that this would require more time. Although these low heritability estimates compared to the majority of U.S. studies are surprising, it is important to note that most of the other similar research world-wide has been conducted with crossbred cattle. The Brooksville data, along with data from the American Brahman Breeders Association National Carcass Evaluation Program, have been incorporated into a national Brahman database for generation of carcass EPD. Based on approximately 1,500 records in the 2005 analyses of the combined data the estimate of heritability for shear force after 14 days of aging was 0.16. As a part of our current major research project, we continue to feed purebred Brahman steers and collect subsequent carcass and tenderness information to add to this national data base. Almost a third of the cattle entering U.S. feedlots come from the states along the Gulf Coast. It is likely that a large number of those are crossbred Brahman. Selecting for tenderness probably has most value as demonstration of intent to improve Brahman tenderness. However, the market does not yet provide economic reward for that improved tenderness. It is important to note that we don’t yet know the genetic consequences for selecting for a tenderness trait—in other words, will this selection result in unwanted change in other traits? Our results suggest that nongenetic intervention strategies are probably equally important to ensure a tender product. If you would like a copy of any of the published results below, please contact me at firstname.lastname@example.org or 352-796-3385. Franke, D. E., D. G. Riley, J. C. Paschal, and C. C. Chase, Jr. 2005.