Pathogenic Effects from Livestock Grazing Riparian Areas
Ohio State University Extension Fact Sheet , LS-5-05 , 2005

Hoorman, J.J.

Most waterborne outbreaks associated with drinking water are the result of either poor construction of wells or major rainfall events that result in increased contamination and water turbidity. Bacteria from livestock can enter streams in runoff or are deposited directly when animals have access to the stream. Sediments in the bottom of streams harbor significantly higher concentrations of bacteria than the overlying water. Bacteria densities in a stream increase with increased grazing pressure. Some microorganisms are encouraged to grow by excess nutrients in the water, especially nitrogen. Low temperatures in surface water, which slow metabolism, generally prolong the survival of pathogens. Ultraviolet light inhibits the survival of bacterial and protozoan pathogens. Habitat competition decreases populations of certain pathogens transported into streams. For more information on the effects of livestock grazing riparian areas see the following fact sheets: Understanding the Benefits of Healthy Riparian Areas, LS-1-05 Negative Effects of Livestock Grazing Riparian Areas, LS-2-05 The Effects of Grazing Management on Riparian Areas, LS-3-05 Best Management Practices to Control the Effects of Livestock Grazing Riparian Areas, LS-4-05 This fact sheet was adapted from Generic Environmental Impact Statement on Animal Agriculture: A Summary of Literature Related to the Effects of Animal Agriculture on Water Resources (G), 1999, Univ. of Minnesota.