Fig. 1

Experimental design and workflow. This study was conducted from the stocker to the finishing stage. Calves during the stocker stage were fed pearl millet (Pennisetum glaucum) hay with soybean hull and corn gluten feed supplement or grazed fall wheat (Triticum aestivum). Following the stocker phase, calves were transported 1,068 km to Canyon, TX, USA for finishing. At the feedlot, cattle were transitioned to a high-concentrate finisher diet for the first 28-d by replacing portions of corn stalks with steam-flaked corn weekly. Cattle remained on this diet for the remainder of the study until approximately 30-d prior to harvest, in which the beta-adrenergic agonists ractopamine hydrochloride (Pre-Ba) was included in the diet. Treatments for this experiment were arranged as a 3 × 2 factorial with factors consisting of three levels of monensin provided during the stocker phase, and whether or not monensin was provided in the feedlot diet following the stocker phase. Ruminal fluids were collected on d 0, 28, 85 (S0, S28, S85) during the stocker phase and on d 0, 14, 28, 56, starting to add Pre-Ba (30 d before harvest) and at the end of finishing stage (F0, F14, F28, F56, Pre-Ba, and Final) during the finishing stage