Animal Industry Report

Extension Number

ASL R2205



Summary and Implications

Poorly managed grazing of beef cattle in riparian areas may contribute to sediment and nutrient loading of Midwest surface waters. In order to develop grazing systems that minimize impacts of grazing cattle on sediment and nutrient loading of pasture streams, knowledge of the effects of grazing management systems on the distribution patterns of cattle is needed. 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). In May and July of 2005 and 2006, and September 2006, constructed off-stream water sites, located in the upland portion of the pastures, were made available to cattle in the CSU and CSR pastures for one week. When no constructed off-stream water was available in the CSU pastures, cattle spent 6.2 and 9.0% of their time in the stream in 2005 and 2006, respectively, and 15.0 and 19.1% within 110 feet of the stream in 2005 and 2006, respectively. In both years, cattle spent a smaller proportion of time in the stream and within 110 feet of the stream in the RS and CSR pastures than in the CSU pastures. In 2005, constructed off-stream water did not alter cattle distribution. In 2006, constructed off-stream water decreased the proportion of time cattle in CSU pastures spent in the stream in July. Patterns of defecation and urination distribution followed that of cattle distribution. Compared to CSU, RS and CSR are potential management strategies for decreasing the proportion of time cattle spend in or near streams. The presence of an offstream water source may be effective in reducing the time cattle spend in or near streams.

Copyright Holder

Iowa State University