Good water quality supports good quality milk production

Hoard's Dairyman: 

Good water quality supports good quality milk production

Date: 
Tue, 05/28/2013

A field study done by Penn State Extension suggests water quality may be linked to dairy herd milk production.

by Abby (Huibregtse) Bauer, Hoard's Dairyman Associate Editor

Penn State Extension recently completed a field study of water quality on Pennsylvania dairy farms. The results shed light on the impact poor quality water may have on milk production. Led by Bryan Swistock, extension water resources specialist in the College of Agricultural Sciences, the goal of the project was to improve awareness of various water quality parameters not always tested but that may impact herd performance.

Penn State Extension offered free water testing to dairy farms across the state. More than 240 dairy farmers were interested in receiving the kits, and 174 water samples from 41 counties were collected and returned to the Agricultural Analytical Services Laboratory at Penn State.

Guernsey cowThe 174 participating farms had between 2 and 1,700 cows and 18 to 2,500 acres of farmland. Overall, the study encompassed 18,000 total cows and more than 51,000 acres. Milk production ranged from 20 to 90 pounds of milk per cow per day.

Samples were analyzed for 13 common water-quality parameters that are part of the laboratory’s basic water testing package. Some parameters incorporated in the test included:

  • pH
  • Total Dissolved Solids (TDS)
  • Nitrate-Nitrogen
  • Hardness
  • Iron
  • Manganese
  • Chloride
  • Sodium
  • Sulfate
  • Copper

The results found that 45 of the samples, or 26 percent of the farms, had at least one water quality issue. Average milk production for those 45 farms was 56 pounds per cow per day, while the 129 farms with good quality water averaged 62 pounds per day. This was a 10 percent difference in milk production between farms with quality issues compared to those with none.

Of the farms averaging more than 75 pounds of milk per cow per day, none of them had water quality problems. For farms milking an average of less than 50 pounds per day, 32 percent had at least one water quality issue. These numbers suggest that water quality could have an impact on milk production.

Water quality issues can be caused by a multitude of problems, and the source is often difficult to identify. Improper well or spring construction or location, poor wellhead or spring protection, nearby activity and land use, and naturally occurring factors (hardness, minerals, pH) can all impact water quality. The best management practice for farms is to test water annually using a certified laboratory. More information about water testing recommendations, understanding test results and more details about this study can be found at the Penn State University website. Click here


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The author is an associate editor and covers animal health, dairy housing and equipment, and nutrient management. She grew up on a dairy farm near Plymouth, Wis., and previously served as a University of Wisconsin agricultural extension agent. She received a master’s degree from North Carolina State University and a bachelor’s from University of Wisconsin-Madison.

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