Title page for ETD etd-0410103-161749


Type of Document Dissertation
Author Devillier, James E.
Author's Email Address jdevillier@agctr.lsu.edu
URN etd-0410103-161749
Title The Louisiana Calf-to-Carcass Program: Growth and Carcass Traits
Degree Doctor of Philosophy (Ph.D.)
Department Animal Science (Animal, Dairy, and Poultry Sciences)
Advisory Committee
Advisor Name Title
D. E. Franke Committee Chair
H. D. Chapman Committee Member
K. W. McMillin Committee Member
Satish Verma Committee Member
T. D. Bidner Committee Member
Robert Hogan Dean's Representative
Keywords
  • steer feedout programs
  • carcass traits
  • feeder calf grades
  • initial feedout weight
Date of Defense 2003-03-21
Availability unrestricted
Abstract
Feedlot and carcass data from 1,533 weanling steers consigned to the Louisiana Calf-to-Carcass program from 1992 to 1998 were used to evaluate the influence of feeder calf grade, sire breed, and initial feedlot weight on growth and carcass traits. Each October, spring born calves were delivered to Clinton, Ruston, or Lake Charles loadout sites. Steers were identified by sire breed, tagged, weighed, assigned a feeder calf grade. Forty-six, 18, 26, and 10 percent of the steers graded large frame-thick muscle, large frame-moderate muscle, medium frame-thick muscle, and medium frame-moderate muscle, respectively. Steers were trucked to a commercial feedlot and sorted into pen lots based on predicted harvest weight and grade. Steers were harvested at approximately 1 cm fat thickness. Steers were grouped by breed of sire origin into American (Beefmaster, Braford, Brahman, Brangus, Gelbray, Red Brangus, Simbrah), English (Angus, Hereford, Red Poll), and European (Braunvieh, Charolais, Gelbvieh, Limousin, Salers, Simmental) sire breed groups. Growth and carcass traits were analyzed with a linear mixed model that included year-location as random and feeder calf grade, sire breed group, and feeder calf grade x sire breed group as fixed sources of variation. Large frame steers had .05 .02 kg greater feedlot average daily gain, 21 4 and 10 3 kg heavier harvest and hot carcass weights, 3.3 .8 cm2 larger ribeye areas and lower yield and quality grades than medium frame steers (P <.01). Thick muscled steers were similar to moderate muscle steers for most traits. European-sired steers had larger ribeye area (P < .05), larger ribeye area per 100 kg of carcass (P < .05), lower yield grade (P < .05), and less fat thickness (P < .05) than English- and American-sired steers. English-sired steers had higher marbling score (P < .05) than American- and European-sired steers. Light weight steers had lower harvest weight (P < .05) and smaller ribeye area (P <.05) than moderate and heavy weight steers. Generally, large frame steers and European-sired steers produced higher yielding carcasses and medium frame steers and English-sired steers produced carcasses with higher quality grade.
Files
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