Effects of an off-stream watering facility on cattle behavior and instream E. coli levels

Authors: WAGNER, KEVIN - Texas Water Resources Institute; REDMON, LARRY - Texas Agrilife Extension; GENTRY, TERRY - Texas A&M University; Harmel, Daren; KNIGHT, ROBERT - Texas A&M University; JONES, C - Texas A&M University; FOSTER, JAMIE - Texas A&M University

Submitted to: Texas Water Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2013
Publication Date: 6/25/2013
Citation: Wagner, K.L., Redmon, L.A., Gentry, T.J., Harmel, R.D., Knight, R., Jones, C.A., Foster, J.L. 2013. Effects of an off-stream watering facility on cattle behavior and instream E. coli levels. Texas Water Journal. 4(2):1-13.

Interpretive Summary: Excessive levels of bacteria from human and animal sources are the leading cause of water quality impairment in Texas, and livestock with direct access to water bodies are potentially a significant source of these bacteria. To help address this source, the effect of providing alternative off-stream watering facilities to reduce manure, and thus bacterial, deposition in or near surface waters was evaluated from July 2007 to July 2009 in Clear Fork of Plum Creek in central Texas. An upstream-downstream, pre- and post-treatment monitoring design was used with off-stream water provided only during the second year of the study. Flow, bacteria (Escherichia coli (E. coli)) concentration, and turbidity (related to sediment concentration) were measured twice monthly. Cattle movements were tracked quarterly using global positioning system collars to assess the effect of providing alternative water on cattle behavior. The study found that when alternative off-stream water was provided, the amount of time cattle spent in the creek was reduced 43% from 3.0 to 1.7 minutes per animal unit per day. As a result, direct deposition of bacteria into Clear Fork of Plum Creek was estimated to be reduced by the same amount. Observed pre- and post-treatment amounts of bacteria transported by the stream suggested similar reductions; however, these findings on the impact of alternative water were complicated by decreased streamflow and increased bacteria concentrations, which likely resulted from increased stocking rate and wildlife contributions due to drought conditions. Finally, unlike previous studies, this study did not find turbidity to be a good predictor of bacteria concentrations. Thus, it was concluded that use of turbidity as an indicator should be determined on a case-by-case basis and used with caution. These results will benefit future best management practice (BMP) evaluations and strengthen efforts to reduce cattle impacts on surface water quality.

Technical Abstract: Excessive levels of fecal indicator bacteria are the leading cause of water quality impairment in Texas, and livestock with direct access to water bodies are potentially a significant source of these bacteria. To help address this source, the effect of providing alternative off-stream watering facilities to reduce manure, and thus bacterial, deposition in or near surface waters was evaluated from July 2007 to July 2009 in Clear Fork of Plum Creek in central Texas. An upstream-downstream, pre- and post-treatment monitoring design was used with off-stream water provided only during the second year of the study. Flow, Escherichia coli (E. coli) concentration, and turbidity were measured twice monthly. Cattle movements were tracked quarterly using global positioning system collars to assess the effect of providing alternative water on cattle behavior. The study found that when alternative off-stream water was provided, the amount of time cattle spent in the creek was reduced 43% from 3.0 to 1.7 minutes per animal unit per day. As a result, direct deposition of E. coli into Clear Fork of Plum Creek was estimated to be reduced from 1.11 x 10**7 to 6.34 x 10**6 colony forming units per animal unit per day. Observed pre- and post-treatment instream E. coli loads suggested similar reductions; however, these findings on the impact of alternative water were confounded by decreased streamflow and increased E. coli concentrations, which likely resulted from increased stocking rate and wildlife contributions due to drought conditions. Finally, unlike previous studies, this study did not find turbidity to be a good predictor of E. coli. Thus, it was concluded that use of turbidity as an indicator should be determined on a case-by-case basis and used with caution. These results will benefit future best management practice (BMP) evaluations and strengthen efforts to reduce cattle impacts on surface water quality.