Factors that affect CAB rate
Most beef producers own at least some Angus cattle. They may have wondered what it takes for their calves to qualify for the Certified Angus Beef (CAB) brand.
CAB’s Gary Fike, beef cattle specialist, and Darrell Busby, Iowa State University (ISU) Extension beef specialist, recently shared data that helps explain. The two presented abstracts at the Midwestern section meetings for the American Society of Animal Science in Des Moines, IA, in March.
Both papers outlined characteristics of Angus-influenced fed cattle that were more likely to meet the 10 CAB carcass specifications (http://www.cabpartners.com/facts/faqs.php#). Mike King, data analyst for CAB, ran the statistical analyses.
“We used our CAB Feedlot Licensing Program [FLP] database of 2005 to 2006 live and carcass records on 21,000 cattle,” Fike said. “Those were sired by Angus bulls on Angus or Angus-based cows.” Busby relied on an analysis of similar 2003-07 data from nearly 24,000 head in the Iowa Tri-County Steer Carcass Futurity (TCSCF).
Percent Angus: The Iowa study showed that the higher the Angus percentage, the greater the CAB acceptance rate. For every 1 percentage-point increase in Angus heritage, CAB acceptance rate rose by 0.093 points. If a pen of 50 percent Angus steers went 20 percent CAB, everything else being equal, a pen of 75 percent Angus steers could be expected to have a CAB acceptance rate of 22.235 percent (0.093 x 25).
Heifer effect: In both studies—the “steer” futurity includes 26 percent heifers—steers had relatively lower marbling scores. Thus, CAB acceptance rates were almost 9 percentage points higher for heifers in the CAB study (33.6 percent vs. 24.7 percent). The Iowa data revealed nearly a 15point increase for heifers over steers.
In-weights: “Feedlot delivery weight was a significant influence,” Fike said. “In general, the lighter the cattle upon arrival, the higher the CAB acceptance rate.” In the FLP study, for each 100-pound (lb.) drop in placement weight, the CAB acceptance rate rose 1.85 percentage points. The TCSCF data showed a 6.6point increase for each 100lb. drop. In the Iowa example, if a pen of Angus-influenced steers placed at 600 lbs. had a CAB acceptance rate of 20 percent at harvest, you could expect a pen placed on feed at 500 lbs. to achieve 26.6 percent CAB acceptance, all else being equal.
Cost of gain: The reports differed on the impact of gain cost on CAB acceptance. As these costs decreased, CAB acceptance rate increased in the FLP study. “For every 2.2-cent drop in the cost of gain, CAB acceptance rose by 1 percentage point,” Fike noted. The Iowa study showed no correlation.
Growth implants: Nonimplanted cattle in the FLP database had a 14-point higher CAB acceptance rate than other cattle, averaging 38 percent CAB. There was no difference in the CAB rate between cattle implanted once and those implanted two or more times. All TC- SCF cattle were implanted at least once with the same product, and no implant-related differences in CAB acceptance were observed.
Rate of gain: Cattle with higher average daily gains (ADG) showed better CAB acceptance rates in the Iowa study. For every 0.1-lb increase in ADG, the CAB acceptance rate increased by 1.45 percentage points. No differences were found in the CAB abstract.
Sorting effect: “Finishing cattle to their optimal quality endpoint pays,” Fike said. “In our FLP database, cattle that were not sorted and shipped as one unit averaged 23.3 percent CAB, while those that were sorted at least once averaged 29.6 percent. Those sorted twice or more averaged nearly 34 percent CAB.” TCSCF cattle are routinely sorted as two harvest groups.
Feed efficiency: In both studies, cattle that had higher feed/gain ratios also had higher CAB acceptance rates. “It looks like a bit of a conundrum that higher CAB-acceptance cattle in our database had a lower cost of gain, yet they were somewhat less efficient,” Fike said. “But we have to remember that these factors are independent of one another.” There may be geographic reasons as well, he added.
Seasonality: Time of year, or season of harvest had an effect on CAB acceptance rate in the Iowa study, but not in the CAB data. The ISU paper concluded cattle that were harvested from October through December had lower CAB acceptance rates than those harvested in other months.
No effect: Medicine cost per head, death loss, days on feed and final live weight showed no relationship to CAB acceptance in either study. In the CAB paper, which included feedlot cattle from New Mexico to Iowa, location had no effect on CAB acceptance rate, nor did relative starting age as calves or yearlings. The Iowa study included mud score, disposition score and region of origin, with no statistical differences in CAB acceptance. — WLJ