title: Factors affecting carcass value and profitability in early-weaned Simmental steers: II. Days on feed endpoints and sorting strategies.
abstract: In a 4-yr study, early-weaned Simmental steers (n = 192) of known genetics were individually fed to determine EPD, performance, and carcass measurements explaining variation in carcass value and profitability across incremental days on feed (DOF) when sorted by HCW, calculated yield grade (YG), or at their highest profit endpoint (BEST). Steers were weaned at 88.0 +/- 1.1 d of age, pen-fed a high-concentrate diet for 84.5 +/- 0.4 d, individually fed for 249.7 +/- 0.7 d, and slaughtered at 423.3 +/- 1.4 d of age. Carcass weight, YG, and marbling score (MS) were predicted using real-time ultrasound throughout the finishing period to calculate carcass value and profitability at 90, 60, 30 d preslaughter and under three individual sorting strategies. Sorting strategies included marketing the 25 and 50% heaviest HCW, the highest YG at d 60 and 30, or the remaining 25% at 0-d endpoints. Independent variables were year, weaning weight EPD, yearling weight EPD, marbling EPD, DMI, ADG, HCW, YG, and MS. Profit was quadratic in response to increased DOF; the greatest economic return was noted on d 30 (pre-slaughter). Final weight, DMI, HCW, MS, and YG increased (linear; P < 0.001) with additional DOF, and ADG and G:F decreased (linear; P < 0.001). Total cost of gain was quadratic (P < 0.001), and incremental cost of gain rose at an increasing rate (quadratic; P < 0.001) with increased DOF. With increasing DOF, HCW importance decreased from 58 to 21%; MS was variable, ranging from 18 to 23%; and YG and DMI were minor contributors to profit variation. Among sorting strategies, final BW and HCW were greater for BEST, whereas other measurements were similar. Sorting individuals by HCW, YG, or at BEST increased profitability 3.70 dollars, 2.52 dollars, or 30.65 dollars over the optimal group DOF endpoint (d 30). Retrospective analyses illustrated that sorting does not need to pinpoint each animal's profit optimum to result in economic gains; rather, increasing HCW and decreasing weight- and YG-related penalties improved profitability. Opportunities may exist with existing and new technology to uniformly allocate cattle into feeding and marketing groups, decrease overfeeding, and increase carcass value and profitability.
authors.affiliation: Department of Animal Sciences, University of Illinois, Urbana, 61801, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Pyatt
authors.forename: L L
authors.initials: LL
authors.lastname: Berger
authors.forename: D B
authors.initials: DB
authors.lastname: Faulkner
authors.forename: P M
authors.initials: PM
authors.lastname: Walker
authors.forename: S L
authors.initials: SL
authors.lastname: Rodriguez-Zas
mesh_terms: D000821:Animal Feed / Q000191:economics*; D000822:Animal Husbandry / Q000191:economics* / Q000379:methods*; D000818:Animals; D001823:Body Composition / Q000502:physiology*; D002417:Cattle / Q000254:growth & development*; D004032:Diet; D016014:Linear Models; D008297:Male; D008460:Meat / Q000191:economics*; D013997:Time Factors; D014886:Weaning