Sorting feeder cattle with a system that integrates ultrasound backfat and marbling estimates with a model that maximizes feedlot profitability in value-based marketing

Abstract

Studies were conducted to evaluate a feeder cattle sorting system for tracking future carcass merit. The Kansas State University (KSU) sorting system combines initial body weight, ultrasound backfat thickness and marbling score with economic data to project the number of days on feed that will maximize profitability. The KSU sorting system was applied, 3 to 4 mo before slaughter, on 4101 yearling steers at two large feedlots located in southern Alberta. In Feedlot 1, steers averaging 408.7 kg (SD = 45.2 kg) were randomly assigned to two treatment groups: sorted by weight (control; n = 856) and sorted by the KSU sorting system (n = 849). In Feedlot 2, steers averaging 494.4 kg (SD = 42.3 kg) were randomly assigned to two treatment groups: not sorted (control; n = 798) and sorted by the KSU sorting system (n = 1598). Whole pens were marketed when the majority of steers in the pen approached the carcass weight and grade characteristics required for optimal return. The KSU sorted steers gained 0.12 kg d−1 faster at Feedlot 1 (P = 0.043) and 0.05 kg d−1 faster at Feedlot 2 (P = 0.036) than control steers. Feed intake, feed efficiency, death loss, warm carcass weight, backfat thickness, l. dorsi area, marbling score and lean meat yield were similar between sorting systems regardless of feedlot. The KSU sorting system reduced dark cutting (B4) carcasses to zero (0.0% KSU vs. 1.3% Control; P = 0.005) and increased AAA quality grade carcasses by 40.8% (31.4% KSU vs. 22.3% Control; P = 0.001) in Feedlot 1. In Feedlot 2, the KSU sorting system reduced over-fat carcasses (Y3) by 47.4% (10.2% KSU vs. 19.4% Control; P = 0.001) and increased AA carcasses by 14.7% (52.3% KSU vs. 45.6% Control; P = 0.003). These changes resulted in the KSU sorted steers being more profitable than control steers by $27.67 head−1 in Feedlot 1 and $15.22 head−1 in Feedlot 2. The increased net return was primarily due to improved weight gains and a more desirable distribution of carcass yield and quality grades. Key words: Ultrasound, carcass uniformity, steers