Figure 1.
Figure 1.

Effect of feeding monensin and Optimase (Alltech, Inc., Nicholasville, KY) on ruminal fluid ammonia (NH3–N) concentration of steers over a 24-h period. Treatments included 40% CP (DM basis) cottonseed meal and wheat middlings–based supplement (Control), a cottonseed meal and wheat middlings–based supplement with slow-release urea and a fibrolytic feed enzyme (Optimase) designed to replace 30% of plant-based CP provided in the Control (OPT), the Control plus 0.40 mg∙kg–1 BW∙d–1 monensin (Rumensin 90; Elanco Animal Health, Greenfield, IN; MON), and the OPT plus 0.40 mg∙kg–1 BW∙d–1 monensin (COMBO). Largest SEM (range = 0.71–0.84). a–cMeans within time with different superscripts differ (P < 0.05).