Effect of a wide range in the ratio of supplemental rumen degradable protein to starch on utilization of low-quality, grass hay by beef steers

Hereford×Angus steers were used in a 14-treatment, 2-period, crossover design experiment to examine effects of a wide range in the ratio of supplemental starch to rumen degradable protein (RDP) on low-quality forage utilization and ruminal characteristics. Steers were given ad libitum access to grass hay (4.9% CP, 42.4% ruminally degradable) and supplemented in a 2×7 factorial arrangement of treatments. All supplements were administered directly into the rumen and delivered one of two levels of ruminally degradable starch (cornstarch grits; 0 and 0.3% of initial BW) and one of seven levels of RDP (sodium caseinate; 0, 0.015, 0.051, 0.087, 0.123, 0.159, and 0.195% of initial BW). Supplementation with RDP increased consumption of forage OM, total OM, NDF, and digestible OM in a quadratic (P