Animal Industry Report

Extension Number

ASL R2206



Summary and Implications

Grazing management can alter the characteristics of the pasture sward. Changes in pasture forage characteristics can affect both the nutritional value of the forage and the environmental impacts of the grazing system. Six 30-acre cool-season grass pastures, containing predominantly smooth bromegrass and bisected by a 642-foot stream segment were grouped into two blocks and assigned one of three treatments: continuous stocking - unrestricted stream access (CSU), continuous stocking - restricted stream access (CSR), and rotational stocking (RS). Forage sward height and mass along with the proportion of bare ground and fecal cover were determined monthly from open and congregation areas within four zones in the pasture. Zones were defined as on the stream bank (bank), from the stream bank to 110 feet from the stream bank (110), 110 feet to 220 feet from the stream bank (220), and greater than 220 feet from the stream bank (upland). Forage samples were analyzed for in vitro dry matter digestibility (IVDMD), crude protein (CP), and phosphorus (P). The occurrence of bare ground and fecal cover was greater in congregation areas than open areas across all pastures. Bare ground was greater along the banks in all grazing management practices but was not different between pastures in the 110, 220, or upland zones. Mean forage CP concentrations were greater and P concentrations tended to be greater in the RS pastures than in CSU or CSR pastures.

Copyright Holder

Iowa State University