What about the water?


by Sally Colby

When farmers are planning new livestock facilities, the intended water source should be a top priority. Drinking water problems can lead to low milk production, and in some cases, affect animal health. The more common problems are aesthetic issues, such as chloride that makes water taste salty but doesn’t directly cause health problems. The presence of excessive iron, manganese, chloride, sulfates and hydrogen sulfide can be difficult to determine, especially if the water supply to livestock is different from that to the home.

Brian Swistock, water resources specialist, Penn State Extension, explained the importance of good quality water for livestock. He reminded producers that dairy cows need 4 to 4.5 pounds of water for every pound of milk produced, and between water and any water in the ration, a single cow drinks more than 300 pounds of water each day.

Swistock said there’s little research on how water quality affects dairy cattle, and there are no firm standards for drinking water. Swistock recalled what he learned from a seasoned dairy Extension educator who said the only way to determine a water quality problem on a farm is collecting water usage data that documents whether usage by cows is lower than it should be. “More importantly,” said Swistock, “segregate cows away from a water source you think is a problem and see how they respond.” This measure is a difficult undertaking for most farms, but the results of separate groups of cattle drinking from different water sources often provides an answer.

“Water supply for livestock is a very high capital investment,” said Swistock. “You want to be sure you have a good return on that investment. Segregating cows (to determine whether a particular water source is problematic) isn’t easy, but the money you spend is worthwhile.”

To prove his point, Swistock referenced a herd that was having milk production issues. They trucked in water from a nearby stream and put a few cows on that water for about a week. “The response was remarkable,” he said. “Then we had to do a lot of research to find out what was causing the problem, but segregating the cows led us to that conclusion.”

Proper well construction is essential to a safe water supply. Most states have standards for wells and capping, including a sanitary well cap made of two pieces with a rubber gasket to exclude small animals, insects and bacteria from groundwater. “Beyond the sanitary well cap, we want casing above ground,” said Swistock. “The casing should extend several feet down into the bedrock, with a grout seal around the casing made of a cement-like material. That’s critical to seal off the space along the casing and prevent surface water contamination. We also like to see a little bit of a slope around the well so it doesn’t attract surface water when it rains.”

Wells that have depressed areas around the cap are usually seen in new construction. The depression occurs after the soil is put back around the well and sinks around the casing during a rain event. Swistock noted that a U.S. Geological Survey showed that about half the well caps examined in a study had obvious insect issues that could lead to bacterial contamination.

Swistock said the popularity of rainwater cisterns comes and goes, but this water collection method is a reasonable consideration because large barn roofs have the potential to collect a lot of water. Collected water is held in a pond or cistern, and can be used to dilute well water and reduce the concentration of harmful substances. “Sometimes we blend water from a rainwater cistern with well water to reduce the concentration to a tolerable level for the cow,” he said. “If nitrates are high in well water, we might mix in rainwater to reduce the concentration.”

Well location on a farm is critical. Wells should not be located in the middle of a field that’s used for growing crops due to frequent soil disturbance that leads to the potential for chemical and manure contamination. No matter where the well is sited, wellhead protection is key in protecting the water supply. For a private well, Swistock suggests a 100-foot circumference where there’s no chance of groundwater contamination by something cows should not drink. “If the well is on a slope, the 100-foot area should extend farther than 100 feet up the slope,” said Swistock. “Have less area below because groundwater tends to move just like surface water – from high area to low area – and we’re more concerned about what’s upslope from the well.”

Swistock listed some common causes of well problems, including improper construction, poor wellhead construction and an unprotected wellhead area. “Some of the things that cause aesthetic issues are natural and will be there regardless of what you do with construction and protection of the well,” said Swistock. “That includes hardness, metals like iron and manganese, hydrogen sulfide gas (with characteristic rotten egg odor) and corrosive water that can lead to high copper concentration because it dissolves copper components out of the water supply.” Dangerous metals such as arsenic can be naturally present in otherwise good quality well water. Other problems can be the result of nearby activities such as manure application, landfills, dumps or industrial production. Water in these areas should be checked for organics, metals and inorganic substances.

Regular water testing can detect potentially harmful substances in water. Swistock recommended using certified, state-accredited water testing labs to maintain a chain of custody. “By chain of custody, we mean the lab comes to the farm and collects the sample,” he said. “You don’t have any interaction with the sample at all – it’s all done by professionals, and they deliver results to you, which are legal documents.”

Swistock advised farmers to actively manage the water supply on the farm, including proper construction siting and wellhead protection. Consider water meters to measure intake, especially if milk production is an issue, although it can be difficult to measure intake accurately if animals drink from multiple sources.

“Everybody thinks the neighbor is causing the problem,” said Swistock. “All too often, folks have to look in the mirror at what they’re doing. Many of these things are self-inflicted.”

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