Intake and Digestibility among Caucasian Bluestem, Big Bluestem, and Switchgrass Compared with Bermudagrass

Warm-season perennial grasses, mainly bermudagrass [Cynodon dactylon (L.) Pers.], have been a major source of hay for ruminant systems across the upper southern United States. This study compares the quality of Caucasian bluestem [Bothriochloa caucasica (Trin.) C.E. Hubbard ‘Caucasian’] (CBS) with ‘Kanlow’ switchgrass (Panicum virgatum L.) (SG), and big bluestem (Andropogon gerardi Vitman) (BBS), relative to ‘Coastal’ and ‘Tifton 44’ bermudagrasses, as forages for the upper south. Four intake and digestion experiments, with associated diet characteristics, were conducted using steers. In experiment (Exp.) 1, CBS regrowth (45 d) compared with initial growth had greater (P = 0.01) daily dry matter (DM) intake (DMI) [2.33 vs. 1.91 kg 100−1 kg body weight (BW)] and apparent DM digestibility (DMD) (664 vs. 617 g kg−1). Initial growth bermudagrass had greater (P < 0.01) DMI than CBS (2.61 vs. 1.91 kg 100 kg−1 BW) and similar DMD (mean = 619 g kg−1). In Exp. 2, initial and regrowth (45 d) CBS, compared with SG, had greater (P < 0.01) DMI (2.06 vs. 1.23 kg 100−1 kg BW). In Exp. 3, regrowth CBS and BBS had similar DMI (mean = 1.83 kg 100−1 kg BW) and DMD (mean = 637 g kg−1). In Exp. 4, initial and regrowth (53 d) CBS and regrowth (57 d) BBS had similar DMI (mean = 2.29 kg 100−1 kg BW), but CBS had greater (P = 0.01) DMD (602 vs. 566 g kg−1). The DMI and DMD of all hays in all experiments (n = 15) were correlated (r = 0.66, P < 0.01). In general all hays can contribute to ruminant production systems.