Submitted to: Agronomy Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 10/29/1996
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: A grazing study was conducted to verify previous small-plot studies that demonstrated early-partial defoliation improved summer herbage quality of warm-season grasses. Fall-born steers (Bos tauras) grazed pastures of 'Cave-in-rock' switchgrass (Panicum virgatum L.) or 'Roundtree' big bluestem (Andropogon gerardi Vitman) during 1993 and 1994. Grazing systems were either 1) continuous (late June-early July into August) or 2) rotational (2 wk short-duration intensive in June, followed by a 4 wk rest period, with a second grazing period into August). Pasture carrying-capacity (steer d ha**-1) for rotational vs. continuous grazing was 2.3 and 2.1 times as much for switchgrass and big bluestem, respectively. Steer average daily gain (kg d**-1) was 1.13 vs. 0.75 for switchgrass and 1.20 vs. 0.93 for big bluestem with rational vs. continuous grazing systems, and steer liveweight gain (kg ha**-1) was 640 vs. 178 and 373 vs. 223 for the same respective grasses and grazing systems. Both greater herbage quality (crude protein and digestible dry matter concentrations) and reduced herbage trampling losses accounted for the observed advantages of rotational over continuous grazing.