Ask dairy farmers about their cows’ feed intake, and they can probably give a detailed accounting of their rations, including forage test results and how they monitor nutrient uptake.

Yet the largest, cheapest ingredient a cow consumes is water, said John Tyson, a Penn State Extension educator.

Cows consume more than 300 pounds of water per day. “If they are going to produce maximum milk, they need to drink,” said Extension water specialist Bryan Swistock.

The pair discussed water quality for dairy herds and water system designs during this week’s Tech Tuesday webinar.

Tyson said water plays an important role in dairy cows, such as milk production, temperature regulation and body functions.

Cows spend only about an hour a day drinking water. Their intake is highest when eating and after milking. It also increases 20 to 100 percent in the summer.

Swistock said little research has been done to determine what level of water pollutants affect cows’ health, and the research that has been done has produced wide-ranging results.

He said the only way to definitively determine if problems in a herd are water related is to keep a group of cows away from the water source in question and see if there is any change.

Testing can also help. There are more than a million private water wells in Pennsylvania, and fewer than 50 percent of them have been tested.

Pennsylvania is also one of only two states that have no regulations regarding private wells.

A well that is properly installed will have ground sloping away from the well head, a casing all the way to bedrock, a grout seal and a sanitary cap that protects against surface contamination and mice infestation, Swistock said.

“Less than 10 percent have this proper, sanitary construction,” he said.

Taste and odor issues can be detected directly or by observing the cows, but health issues from pollutants are not easily detected without testing, Swistock said.

He encouraged farmers to test their water annually and to vary the timing to detect changes through the seasons.

Samples should be sent to a certified testing lab. But if the testing is for legal documentation, the lab will have to come out and collect the sample to maintain a legal chain of custody.

For example, if gas drilling is scheduled near the farm, having a certified lab test the water before drilling will establish a benchmark for water quality.

When tests show a problem, “all too often people need to look in the mirror” instead of pointing to the neighbor, Swistock said.

He also encouraged farmers to install water meters to monitor water intake, especially if milk production is low.

Farmers should also seek help interpreting the results of water tests in relation to herd performance.

Watering systems must be designed to handle peak water demands. Cows will drink 5 to 10 gallons of water a minute, Tyson said.

When carrying water to a cow that has just calved, “it can become a bucket brigade when they are thirsty,” he said.

Open water toughs work well in a freestall barn, and there needs to be at least two in each group so “a boss cow can’t control the water supply,” Tyson said.

When waterers are installed in walkways, he said, there should be a minimum of 16 feet clearance so cows can easily drink while other cows pass behind them. He also said he likes to install the “longest watering station I can fit in that space” to allow more cows to drink at the same time.

Farmers should also take time when constructing their barns to make sure that water supply lines and pumps are adequate to bring as much water as needed to the cows.

“You can only cram so much water into a pipe,” Tyson said.

For tie-stall barns, watering bowls should be placed to allow a cow to drink properly, he said. Some farmers install one watering bowl per stall to help maximize milk production and eliminate problems caused by dominant cows.

Watering systems should also be designed for failure. “Don’t let one piece stop all water flow,” Tyson said.

Larger farms should consider drilling a second well. “I have never known a farm to be disappointed to have two wells when they needed them,” Tyson said.

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