Summary and Implications
Presence of cattle near pasture streams may increase the probability of bare ground and feces on streambanks and increase the risks of sediment, phosphorus, and fecal pathogen loading of water resources through direct deposition or transport in precipitation runoff. Management techniques such as providing off-stream water sources or managing cattle access to pasture streams through rotational stocking or use of stabilized stream access sites may limit the amount of time that the cattle spend near the stream, decreasing the risks of non-point source pollution. Six 30- acre cool-season grass pastures, bisected by a stream, were split into two blocks with three treatments per block. Treatments were: continuous stocking with unrestricted stream access (CSU), continuous stocking with access to the stream restricted to a 16-foot wide stabilized stream crossing (CSR), and rotational stocking (RS). Each pasture was stocked with 15 fall-calving Angus cows. For two weeks in each month from May through September, at least one cow in each pasture was fitted with a GPS collar programmed to record cow position at 10 minute intervals. Off-stream water was made available to cows in pastures with the CSU and CSR treatments for one week of the twoweek position measurement period in each month., Each pasture was divided into four zones to analyze position data; in the stream or on the streambank (stream zone), 0 to 110 feet from the streambank (110 zone), 110 to 220 feet from the streambank (220 zone), and greater than 220 feet from the streambank (upland zone). The combination of the stream and 110 zones were defined as the streamside zone. Cattle in both RS and CSR pastures spent (P < 0.10) less time within the stream and 110 zones than CSU pastures in June and May, and July, respectively. Off-stream water availability had no meaningful effect on cattle distribution in the CSU and CSR pastures. With increasing temperatures, the probability that cattle were present in the streamside zone of CSU pastures increased more rapidly than CSR pastures.
Iowa State University
Schwarte, Kirk A.; Russell, James R.; and Morrical, Daniel G.
"Microclimate Effects on the Temporal/Spatial Distribution of Beef Cows
Grazing Cool-Season Grass Pastures by Different Management Practices,"
Animal Industry Report:
AS 656, ASL R2529.
Available at: http://lib.dr.iastate.edu/ans_air/vol656/iss1/50