Does Your Dairy have Good Water?

Posted: June 28, 2013

Cows need a continuous supply of good quality water in order to continue to produce good quality milk.

While many people never step foot on an actual dairy farm, they do reap many benefits from the items produced there.  An average American consumes over 200 pounds of milk and 32 pounds of cheese a year.  In order to enjoy that cold glass of milk or the cheese on our cheeseburgers, cows need a continuous supply of good quality water in order to continue to produce good quality milk.

Many dairies in Pennsylvania commonly use springs or wells to provide water for their cattle. All water sources used on a farm, especially springs and wells, should be tested annually for things such as iron, sulfates and nitrates. While these nutrients occur in almost any water source, concentrated levels of any one can cause health issues for dairy cows so it is important to know what exactly you are dealing with.

A recently completed study of water supplies on Pennsylvania dairy farms conducted by Penn State Extension found that about a quarter of those tested had at least one water-quality issue. And 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.While most dairy farms routinely conduct bacteria testing of their water supplies, additional testing for salts, metals and other parameters that can affect herd performance are less frequently tested.

In the fall of 2012, Penn State Extension offered free water testing for dairy farmers across Pennsylvania. The objective of the project was to increase awareness of various water-quality parameters less-frequently tested. These less-tested parameters may explain chronic herd performance issues.

Two hundred forty-three dairy farmers who expressed an interest in water quality received water test kits and 174 water samples from 41 counties were returned to the Agricultural Analytical Services Laboratory at Penn State. That equates to a 72 percent participation rate.

The water samples were analyzed for 13 common water-quality parameters that are part of the lab's basic livestock water package. Ninety-eight percent of the water samples came from private water wells or springs on the dairy farms. The farms in the study encompassed 51,000 acres and 18,000 cows with an average milk production level ranging from 20 to 90 pounds of milk per cow per day. Only six -- 3 percent --of the farms in the study had water meters to document water consumption by their herd.
Overall, 45, or 26 percent, of the water supplies had at least one water-quality issue. 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.

Interestingly, none of the farms with high milk production (above 75 pounds of milk per cow per day) had existing water quality problems. While 32 percent of farms with low milk production --below 50 pounds of milk per cow -- had at least one potential water-quality problem.

Penn State Extension encourages farmers with water-quality issues to install water meters to evaluate the herd's water-consumption level. It is also recommended to provide 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.

For more information on the study can be found on a taped webinar available on our Penn State Water Resources web site at