Effect of diet mixing strategies on growth performance and carcass characteristics of feedlot cattle.

Feeding cattle a total mixed ration (TMR) instead of offering dietary ingredients separately (instead of individually) is generally recommended. Feeding TMR enhances production by reducing feed sorting, decreasing manual labor, and preventing digestive diseases. However, producing TMR requires a specialized mixer that can be expensive and necessitates trained personnel and regular maintenance. Furthermore, some roughages need prior processing before adding to the mixer. Consequently, providing TMR is a methodology hard to adopt by small-sized farm operations. The goal of this study was to evaluate growth performance and carcass characteristics of feedlot cattle offered a TMR or non-mixed ration (NMR; hay and concentrate were provided separately). Angus-Simmental cattle (324.8 ± 29.6 kg) were fed using either a TMR strategy (TMRS; n = 29) or a non-mixed ration strategy (NMRS; concentrate and hay were fed separately; n = 30). Steers were housed individually and fed once a day using individual feed bunks. Irrespective of the treatment, feed offered was subjected to a slicked bunk management. For the NMRS treatment, each bunk was bisected by a wooden plunk bolted to it, for hay and concentrate to be offered in one half each. The ratio hay-to-concentrate (7-to-93) offered was the same between treatment groups. Steers were weighed every 28 d while feed offer and refusals were recorded daily. Post slaughter, yield grade, hot carcass weight, back fat, ribeye area, kidney-pelvic-heart fat, and quality grades (marbling, skeletal maturity, lean maturity) were recorded at the slaughterhouse. Data were analyzed considering the fixed effect of treatment. No differences (P ≥ 0.15) were observed for growth performance or carcass characteristics between treatments. These results likely stem from bunk management practices, allowing adjustments in the amount of feed offered based on the amount remaining in the bunk each day, thus maintaining similar feedstuff ratios across treatments. However, the feed management approaches used in this study might not align with animal group housing, conventionally used in feedlot operations, due to bunk competition and diet selection.