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Title: Genetic analyses of beef traits of crossbred and purebred Romosinuano, Brahman, and Angus steers

item Riley, David
item Chase, Chadwick - Chad
item MILLER, M
item BROOKS, J
item Phillips, William
item Coleman, Samuel
item OLSON, T

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 12/7/2007
Publication Date: 9/8/2008
Citation: Riley, D.G., Chase, C.C., Miller, M.F., Brooks, J.C., Johnson, D.D., Phillips, W.A., Coleman, S.W., Olson, T.A. 2008. Genetic analyses of beef traits of crossbred and purebred Romosinuano, Brahman, and Angus steers [abstract]. Southern Association of Agricultural Scientists. Journal of Animal Science Supplement. 86(E-3):4.

Interpretive Summary:

Technical Abstract: The objective herein was to estimate heterosis and breed effects for beef traits of steers produced by purebred and crossbred matings of Romosinuano, Brahman, and Angus. Steers (n = 469) were spring-born from 2002 to 2004 and weaned at an average of 7 mo of age. They were transported to Oklahoma and grazed winter wheat for 6 mo. They were then fed in feedlot pens for 3 periods: 97, 125, and 153 d, and commercially slaughtered. Traits analyzed were hot carcass weight (HCW), longissimus muscle area (LMA), marbling score (MS), 12th rib fat thickness (BF), and Warner-Bratzler shear force after 7 d aging (SF). Mixed models included fixed effects: year, sire breed, dam breed, sire breed-dam breed interaction, days on feed, age at slaughter, and slaughter group. Sire within sire breed was a random effect. Significant estimates of heterosis were obtained for Angus-Romosinuano for HCW (29.7 ± 8.2 kg; 8.7%) and LMA (3.4 ± 1.2 cm2, 4%); for Brahman-Romosinuano for HCW (27.1 ± 6.1 kg; 9.1%), BF ( 1.77 ± 0.55 mm; 17.8%), and LMA ( 2.23 ± 1.2 cm2; 3%); and for Brahman-Angus for HCW (48.7 ± 7.2 kg; 15.8%), BF ( 2.85 ± 0.64 mm; 21.9%), and LMA (5.63 ± 1.4 cm2; 7.5%). Heterosis was not detected (P > 0.35) for MS or SF. Romosinuano direct breed effects (P < 0.01) were to decrease HCW (–47.9 ± 9.4 kg), MS (–56.7 ± 21.1), and BF (–5.01 ± 0.85 mm). Brahman direct effects (P < 0.01) were to increase HCW (32.9 ± 10.6 kg) and SF (0.73 ± 0.3 kg), and to decrease MS (–158.5 ± 23.8). Angus direct effects (P < 0.01) were to increase MS (215.1 ± 23.9) and BF (3.38 ± 0.97 mm), and to decrease SF (–0.7 ± 0.25 kg). Use of Romosinuano in crossbreeding programs with Brahman may result in larger heterosis than expected for some carcass traits. The Romosinuano effects on MS and SF suggested no beneficial effect on US quality grade or tenderness, but there may be a relative Romosinuano advantage as compared to Brahman with regards to these traits.