320 - Effect of Breed of Sire and Calving Season on Feedlot Performance and Carcass Characteristics

Monday, June 27, 2022

9:20 AM – 9:35 AM CT

Location: Oklahoma City Convention Center, 301 A/B

Presenting Author(s)

MM

Mikayla F. Moore

Graduate Research Assistant
Oklahoma State University
Stillwater, Oklahoma

Author(s)

Emma A. Briggs

Graduate Research Assistant
Oklahoma State University
STILLWATER, Oklahoma
BW

Blake K. Wilson

Associate Professor
Oklahoma State University
Stillwater, OK
RR

Ryan R. Reuter, n/a

Professor
Oklahoma State University
Stillwater, OK
Paul A. Beck, PhD

Associate Professor
Oklahoma State University
Stillwater, Oklahoma
Andrew P. Foote, PhD

Assistant Professor
Oklahoma State University
Stillwater, Oklahoma
David Lalman, Professor

Professor
Oklahoma State University
Stillwater, OK

Abstract: Four years of feedlot performance and carcass characteristics were pooled on spring-(SPRING) and fall-(FALL) born steers (n=460) into a mixed model to evaluate the effects of calving season, sire breed (Angus [AN], Charolais [CHAR] or Hereford [HER]) and their interaction on feedlot performance and carcass traits. Initial and final BW, DOF, ADG, DMI, and G:F were evaluated as performance measures and HCW, YG, FT, REA, and MS were collected at harvest. There was no season by breed interaction for entry or final BW (P >0.05). SPRING steers (400.2 kg, 686.4 kg) weighed more than FALL (350.9 kg, 668.3 kg) upon entering and leaving the feedyard (P < 0.001). CHAR weighed 14.3 kg less than AN upon feedlot entry (P=0.01) although final BW did not differ by breed (P >0.05). SPRING steers (21.8 kg/d) consumed more feed than FALL steers (18.8 kg/d; P=0.002), but there was no difference in gain:feed due to calving season nor sire breed (P≥0.575). A calving season by sire breed interaction was present for ADG and DOF (P≤0.014). FALL AN (1.70 kg/d) and FALL HER (1.80 kg/d) gained more than FALL CHAR (1.55 kg/d;P < 0.001) and FALL AN were fed over a shorter period than FALL CHAR and FALL HER (P≤0.006). However, average daily gain of SPRING calves did not differ by breed (P >0.05). There was a tendency for FALL (400.9 kg) steers to have lighter carcasses than SPRING steers (407.9 kg; P=0.068). HER carcasses were 18.0 kg heavier than AN carcasses (P < 0.001), but did not differ from CHAR (P=0.13). CHAR had larger REA (93.5 cm²) than both AN (87.7 cm²) and HER steers (88.5 cm²;P≤0.001). Fall-born steers had less YG than spring-born steers (P < 0.042). Feedlot performance was generally less for fall-born steers finished during the winter months. Under these conditions, numerous performance and carcass traits were influenced by the interaction of breed and season.