97 Use of genomic testing for predicting performance of finishing steers

Abstract

Abstract Genomic testing is a commercially available tool that has the potential to be beneficial in selecting cattle for retained ownership, as well as making management and marketing decisions after finishing. The objectives of this study were to determine if commercially available genomic tests are predictive of differences in finishing performance of steers from sires selected based on divergent growth and milk EPDs. The commercial genomic testing of milk and average daily gain (ADG) scores used in the current experiment were based on Neogen Igenity Beef test results. Two trials were conducted at the OSU Willard Sparks Beef Research Center in Stillwater, Oklahoma. These experiments used two sets of steers from the OSU Range Cow Research Center (400 ± 13 kg, n = 154) from a spring calving cowherd (South Range Unit) and a fall calving cowherd (North Range Unit) of primarily Angus ancestry. Following preconditioning and a wheat pasture stocker program (South Range) or dry lot growing period (North Range), steers were allocated into pens (n = 5 animals/pen) by Igenity ADG Score: low growth (LG) had scores ranging from 1 to 4, medium growth (MG) had scores from 5 to 6, and high (HG) had scores from 7 to 10. Steers were blocked by initial BW and fed a step-up diet for 30 d before being switched to a finishing ration diet (8% prairie hay, 20% Sweet Bran, 62% dry-rolled corn, 5% liquid supplement, and 5% dry supplement [DM basis]). Cattle were fed ractopamine hydrochloride for 30 d before slaughter. The heavy block was on feed for an average of 136 d, while the light block was on feed for an average of 160 d. Data were analyzed as a randomized complete block design using the mixed procedure of SAS (SAS Inst. Inc., Cary NC) with pen as the experimental unit and finishing pen within block as the random statement. During the feeding period, HG steers gained more rapidly than MG or LG steers, with ADG of 2.08, 1.94, and 1.90 kg/d, respectively (P = 0.04). Because gains were greater, BW at slaughter for the HG steers was greater than MG and LG, averaging 690, 669, and 660 kg, respectively (P = 0.04) and hot carcass weights were greater for HG than MG and LG, averaging 438, 426 and 418 kg, respectively (P = 0.02). There were no other differences (P > 0.19) in carcass characteristics among steers. These data suggests that the genomic testing is accurate predictor of performance and can be used by producers can make better marketing decisions in selecting cattle for the retained. Genomic testing could be very beneficial for producers looking to minimize risk and maximize performance in their herd.