Despite the importance of water quality to livestock, limited research has examined the variability of water composition and its impact on animal performance. Before dairy producers spend significant amounts of money on water-treatment systems to correct water-quality problems, they should first implement sound water-management practices and provide an adequate volume of water to meet needs during peak demand, according to Dana Tomlinson, research nutritionist from Zinpro Corporation.
Sound water-management practices include:

  • Cleaning water devices on a weekly, if not daily, basis
  • Ensuring the water system provides adequate volume to meet water needs
  • Water devices are designed and located to allow animals to drink comfortably
  • At least 3.5 inches of accessible linear waterer space per cow

Recently, more than 5,500 water samples were collected from livestock operations throughout the United States. Results from this survey indicate that water quality on a number of dairies could be limiting animal performance. Key highlights from the survey include:

  • Median mineral concentration of water collected did not exceed the upper desired limits for any minerals. However, 21 percent to 31 percent of the individual samples exceeded upper desired levels of calcium, sodium and sulfates for livestock.
  • More than 35 percent of the samples contained iron and manganese at concentrations above desired levels.
  • 37.2 percent of samples had a combined sulfate and chloride content of greater than 500 ppm. Beede (2006) noted that, based on field experience, water having a combined sulfate and chloride concentration of greater than 500 ppm may negatively impact cattle performance, especially fresh cows.

Most producers assume water quality affects dairy cow performance. However, it is unclear whether subtle and persistent problems that decrease production or health of a dairy cow are related to water quality. Existing research indicates that elevated levels of nitrates, sulfates, iron and total dissolved solids in water negatively impact animal performance.

The best option for ensuring good water quality is to protect the water source from contamination. Due to water potentially not being the limiting factor on a dairy, the cost associated with installing water treatment equipment and potential for a treatment system to be ineffective (wrong system, improper installation, lack of maintenance), producers should try to utilize an alternative water source (such as hauling in fresh water) for a period of time to see if cows respond favorably to improved water quality.