Eastern gamagrass management for pasture in the Mid-Atlantic region: ii. diet and canopy characteristics, and stand persistence
Eastern gamagrass [Tripsacum dactyloides (L.) L.] (EG), a native warm-season perennial grass, lacks evaluation for use in grazing systems. Our objective was to test EG in a 4-yr experiment to estimate forage mass (FM) that maximizes steer (Bos taurus) performance and pasture productivity. Pasture canopy characteristics, diet selection by grazing steers, and stand persistence from EG continuously grazed at Short, Medium, and Tall heights and two rotationally stocked treatments were compared with continuously stocked ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] (BG). The EG had proportionally more green leaf (78.2 vs. 24.5%), less stem (4.4 vs. 45.2%), less heads (0.4 vs. 5.6%), and similar dead tissue (17.0 vs. 24.8%). Plant fractions were similar in proportion among EG treatments. Digestible leaf mass was greater in EG than in BG (P < 0.01; 713 vs. 292 kg ha–1) and dominated the EG canopies with a linear (P < 0.01) increase in leaf mass with increasing FM (194–922 kg ha–1). Diets were similar in IVTOD (738 g kg–1), CP (151 g kg–1), and NDF (654 g kg–1) when continuously stocked but greater (P < 0.01) in IVTOD (791 g kg–1), and least in NDF (624 g kg–1) from the rotation. Stand declined linearly (P = 0.09) with decreasing FM (Tall = 34.5 and Short = 11.7% basal cover) but was similar between the two rotational systems (35.5%). Continuously stocking EG at about 38 cm gave greatest steer daily gain but rotations may prevent declines in stands with some sacrifice in gains.