Assessment of Nitrate and Escherichia coli in Cattle Drinking Water Troughs in Central California Dairy Farms

Nitrate and Escherichia coli (E. coli) are two common pollutants present in dairy cattle drinking water troughs. At elevated levels, both pollutants can be of immediate health concern, but longer-term exposure to these pollutants at higher levels can also increase the risks of decreased fertility, diseases, and decreased milk production. This research focuses on evaluating several farms in central California and aims to survey levels of both nitrate and E. coli levels across the period of a year, while also determining the sources of each contaminant for assessing drinking water quality conditions and to help inform any future treatment or prevention considerations, which can potentially improve water quality. From the troughs sampled, nitrate was elevated in a significant portion (47%), and while not at highly toxic levels, the nitrate levels may be harmful over long-term exposure, especially if their feed has high nitrate content as well. The source of each contaminant is different; however, research showed nitrate already existing in groundwater supplies. In terms of E. coli, in general, groundwater had much lower levels of E. coli than water in the troughs, suggesting that the cattle themselves and trough surroundings are major contributors of E. coli in trough water.