A recently completed study of water supplies on Pennsylvania dairy farms found that about a quarter of those tested had at least one water-quality issue. The average milk production for these farms was about 10 percent lower than farms with good water quality.

Dairy farms rely on good quality water to ensure maximum milk production and herd health, according to study author Bryan Swistock, extension water resources specialist at Penn State University.

More than 240 dairy farms in Pennsylvania participated in a study last year in which they received water test kits and sampled their water. One hundred and seventy four water samples from 41 counties were returned to the Agricultural Analytical Services Laboratory at Penn State.

“Overall, 45 of the water supplies, or 26 percent, had at least one waterquality issue,” Swistock said. “Average milk production for these 45 farms was 56 pounds per cow per day, compared to 62 pounds on the 129 farms with good water quality.”

“Penn State Extension encourages farmers with water-quality issues to install water meters to evaluate the herd’s water-consumption level,” Swistock said. “We also recommend providing alternative sources of water to a subset of the herd to collect more evidence of the potential effect of these water quality problems on performance.”