Intake and Digestibility of Big Bluestem Hay and Baleage
2012
Burns, J. C. | Fisher, D. S.
Big bluestem (Andropogon gerardi Vitman) has potential to be a source of preserved forage for the mid-Atlantic Region. This 3-yr study compares its preservation as hay, direct-cut (DC) baleage, and wilted (WT) baleage when harvested in the late-boot to heading stage. The DC baleage averaged 373 g kg⁻¹ dry matter (DM) and WT averaged 536 g kg⁻¹ DM. The DC baleage had a pH of 5.2 vs. 5.6 (P = 0.06) for the WT. Steer (Bos taurus) intakes of the DC and WT baleage were similar (1.72 kg per 100 kg body weight) and greater (P = 0.07) than intake of hay (1.52 kg per 100 kg body weight). Apparent total tract DM digestibility was greater (P = 0.03) for hay (545 g kg⁻¹) than the similar (504 g kg⁻¹) baleage treatments. Steers selected a diet with greater in vitro true DM disappearance (71 g kg⁻¹) and not altered by preservation method. Rumination chews per day and chews per minute and total number of boluses per day were greater (P ≤ 0.10) for DC baleage, reflecting its greater (P = 0.07) DM intake. Big bluestem dried rapidly providing an advantage for conservation in humid regions. Forage cut by 0900 h reached 800 g kg⁻¹ DM by 1700 h when tedded and by 1100 h the second day in narrow swath. Forage cut at 1700 h reached 800 g kg⁻¹ DM by 1500 h the next day when tedded but not until 1100 h the third day in narrow swath. Big bluestem harvested at early heading is of moderate quality when preserved as hay or DC baleage and dries rapidly giving it a role in beef production systems in the humid mid-Atlantic Region.
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