Angus influence affects efficiency, carcass merit
Successful producers have always tried to raise high-quality, high-perform ing cattle, but may have felt compelled to choose one ideal over the other. That’s not necessary, according to a recent analysis of data from the Iowa Tri-County Steer Carcass Futurity (TCSCF).
What is the effect of per cent Angus genetics on per formance in the feedlot and on carcass merit? Mark Mc- Cully, supply development director for Certified Angus Beef LLC (CAB), worked with colleagues Larry Corah and Mike King at CAB, and Iowa Extension beef special ist Darrell Busby to present a research summary.
The data came from 18,250 steers and heifers consigned to TCSCF from 2002 to 2007, and categorized into quartiles by their degree of Angus in fluence: Low, Half, Three quarter, or Straightbred An gus (Table 1). After a minimum 28-day preconditioning period be fore arrival at any of 10 TSCSF feedlots, cattle were weighed and given initial implants, vaccinations and body scores within their first four days on feed. All were given similar implants and health treatments and fed the same energy level.
McCully presented and discussed the data earlier this year at the Southern Section, American Society of Animal Science meetings in Dallas, TX. The results may have re vealed the solution to pro ducers’ dilemma. Research showed that Angus influ ence had a positive effect on a number of performance and carcass factors.
“For years, breed composi tion has been recorded on cattle enrolled in the futu rity,” McCully says. “These data are now some of the most comprehensive avail able where genetics are quantified.”
Straightbred Angus cattle showed better feedlot health and lower treatment costs than cattle with less Angus influence. The straightbred average treatment cost of $4.60 per head was $3 less than that for the lowest- Angus-influence cattle.
Moreover, that was less than the treatment costs for the typical crossbreds in the middle quartiles. Over all health significantly im proved with increased An gus influence. Straight Angus cattle had a sickness rate of 14.8 percent, while cattle with low influence had a rate of 22.8 percent.
“This is one of the most interesting findings in the analysis, but one we don’t have a thorough explana tion for,” McCully says. “The data showed less sickness and reduced treatment cost as the percent Angus in creased, but pre-feedlot health protocols were pre scribed to be the same for all cattle. So, this appears to be a genetic effect.”
Some of the earliest data on breed-type effect on health came from a 1984 doctoral dissertation on the effects of pre- and post-tran sit potassium levels, receiv ing diets and deworming on highly stressed calves, by Frank Brazle at Kansas State University.
The published table re ferred to “Breed Combina tion,” but the four descrip tions noted only color, not uncommon for public re search.
“We can safely as sume that the medium frame solid blacks we noted back then were pre dominantly Angus,” Brazle says now. In that study, the 2.79 percent mortality rate in groups of straight blacks compared to 18.39 percent in black baldies of the same frame size, 12.93 percent in all black baldies, and 6.34 percent in mixed-color lots. McCully adds there has been recent data showing that respiratory disease is genetically influenced. He says it is possible that an unintentional selection for respiratory disease resis tance may have occurred through popular Angus sire lines.
“It is certainly an area that needs more research,” he says. The TCSCF study also noted relatively fewer days on feed for straight Angus, and the highest average daily gain of all groups.
Finally, ability to earn premiums for carcass mer it increased with Angus influence. Marbling scores trended higher in a direct correlation with percentage Angus in fluence.
While nearly a third of straight Angus cattle achieved CAB acceptance or USDA Prime, the low-influ ence cattle made only 9.3 percent CAB and only 0.3 percent qualified for Prime.
On the other hand, less than 1 percent of the straight Angus cattle were discount ed as USDA Standard, com pared to more than 5 per cent of the low Angus.
“Angus cattle are known for their carcass merit and marbling ability, specifically, so the improvement in qual ity grade due to increased Angus genetics came as no surprise,” McCully says. Whether the data rein forced knowledge or revealed something new, he says, “We hope it will benefit produc ers when they are making genetic selections for their next calf crop.” He notes that the num bers say producers can ex pect both higher perfor mance and quality grades from straight Angus cattle.
“Wise cattlemen will make sure they are looking at all the facts when they make decisions on genetics,” Mc- Cully says. For the complete abstract and slide show, see http:// www.cabpartners.com/ news/EducatorMailing/SS AbstractEffectPercentag eAngus.doc and http://www.cabpartners.comnews/ EducatorMailing/SSEffect AngusMcCully. — WLJ
TABLE 1: Effect of % Angus on carcass merit, health and perfor mance among Tri-County Steer Carcass Futurity calves, 2002- 2007.