The use of well water is common on Irish farms, but although it is free, you should still take annual samples to ensure the water quality is good enough for lactating cows. Unrestricted access to clean, fresh drinking water is essential for dairy cow productivity, health and welfare. Dairy farms rely on good water quality and palatability to help maintain intakes at grass, and reduce the risk of water-borne mastitis infections such as pseudomonas. Possible sources of contamination:
  • Farm animals/wild animals having unrestricted access to the source of the well;
  • Inadequate protection from contamination from surface runoff;
  • Slurry/sewage spreading;
  • Proximity to a faulty sewage system;
  • Inadequately maintained wellhead and/or surrounding area.

Water consumption

For cows, water is essential for regulation of body temperature; rumen fermentation; flow of feed through the digestive tract; nutrient absorption; metabolism; and waste removal. A cow’s water consumption is usually between 60-80L/day. But during the recent extreme weather water intake can increase by 30-50%, meaning cows could be drinking more than 90L/day. Water quality issues can result in health issues for dairy cows, and/or reduced water intakes. It can also have an impact on milk quality.

Reduced water intake may not be caused by water quality issues. Other issues - which could include stray electrical voltage - may be the cause.

In this situation, cows are often afraid to drink from the trough. But it could be missed in a grazing herd where cows might only be seen when herding the cows. A quick check of the trough before cows enter and after cows leave a paddock can easily detect tray voltage.

Testing water quality

Taking a sample once a year should be good enough. If you have had a issue with contaminated water supply it is important that you continue to monitor and control the situation. The bacteria that should be tested for are coliforms, E.coli and Enterococci. Microbiologically contaminated water can:
  • Cause elevated total bacteria counts (TBCs) and thermodurics in milk;
  • Contaminate the household supply and may cause human health problems.
The ideal place to sample well water is at the point of use. This usually means taking a sample from a tap. The tap should be disinfected and the sample taken in a sterile bottle. If possible, you should take a few samples from different places.
WATER QUALITY WELL WATER