Effects of dietary composition and feeding management regimen on liver abscess prevalence, growth performance, and carcass outcomes of feedlot steers

We investigated the independent and in- teractive effects of dietary starch concentration and feed- ing management regimen on growth performance, carcass characteristics, and prevalence of liver abscesses in finish- ing beef cattle. Beef steers (n = 720) were assigned to 48 pens in a randomized complete block de- sign, with treatments arranged in a 2 × 2 factorial (12 pens per treatment). Factors were finishing diets with ei- ther low (49.1%; CON) or high (64.4%; HOT) starch con- centrations and feeding management regimens designed for consistent feed delivery (REG) or randomized varia- tions (ERR) in both feed quantity (85% followed by 115% of the previous 4-d average randomly once per week) and delivery time (randomly delayed for 1, 2, 3, or 4 h twice per week). No interactions between diet and feeding management regimen were detected for growth performance, carcass outcomes, or liver abscess prevalence. Steers fed HOT had greater liver abscess fre- quency (55.1% vs. 33.4%) and a greater proportion of liver scars (46.7% vs. 34.0%) compared with CON. Steers consuming HOT also had less final BW, ADG, DMI, hot carcass weight, marbling score, and calculated YG versus CON. Feeding management regimen did not affect liver abscess frequency, growth performance, or carcass merit. Feeding a high- starch diet increased liver abscess prevalence and de- creased growth and affected carcass outcomes. In contrast, erratic feeding management did not affect liver or produc- tion outcomes.