|Horne, W - TEXAS TECH UNIVERSITY|
|Byrd, J - TEXAS TECH UNIVERSITY|
Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2003
Publication Date: February 14, 2004
Citation: Coleman, S.W., Riley, D.G., Chase, C.C., Phillips, W.A., Horne, W.J., Byrd, J.H. 2004. Evaluation of Romosinuano as straightbreds and crossbreds with Angus and Brahman: carcass traits [abstract]. Journal of Animal Science 82(2):5. Technical Abstract: Typically the adaptation of beef cows that is required in the subtropics has been accomplished by using percentage Brahman breeding. They are well adapted for the stresses of the subtropical environment, but carcass merit of market animals has been questioned. A herd of Romosinuano (R), a Bos taurus, criollo breed native to Colombia has been developed at STARS, and were evaluated in a 3 breed diallel crossbreeding study with Angus (A; temperate Bos taurus) and Brahman (B; tropical Bos indicus). Calves (n=135) born in 2002 were straightbred AA, BB and RR, or crossbreds (RB,BR,RA,AR,BA,AB;letters indicate breed of sire and dam, respectively). Steer calves were weaned in late September and shipped 2025 km to El Reno, OK for growing and finishing, after grazing wheat pasture until May, 2003, they were finished on a conventional feedlot diet. Steers were serially slaughtered at 97,125 and 153 days on feed. Carcass information was collected after a 48-hr chill at 4° C. Calf age at weaning and days on feed were included as continuous variables. Sire within breed was a random term Back fat (BF) and yield grade (YG) increased (P< 0.10) over days on feed at an increasing rate for BA and at a decreasing (P< 0.10) rate in AA, BB, and RB. Marbling score increased (P< 0.10) linearly with days on feed more rapidly with AA and BB than with RR, while crossbreds were not different from RR. Direct effects for A, B, and R for carcass weight, BF, YG and marbling were 30.6**, and 193**,-99**, and -94**, respectively (*=P<0.05;**=P< 0.01). Heterosis (P<0.05) was observed among all combinations for carcass weight, and for A with B and B with R for BF and YG. Angus influence increased the percentage grading choice. Tropically adapted (R or B) were similar in number choice (~70%) when crossed with A.