Editor’s note: The following is based on a presentation this week at the Cornell Nutrition Conference. 

Q: How can you help your clients with water quality?

A: Abundant, high-quality drinking water is the most important essential nutrient for dairy cattle, points out David Beede, dairy nutritionist at Michigan State University.

Beede offers the following suggestions for monitoring water quality on your clients’ farms.

There are two basic questions to explore:

  1. Is water intake normal given the physiological state of the animals and the environment?
  2. Are there some anti-quality factors (or pollutants) present in the water that are affecting how the cows consume it?

In assessing the first question, it is important to measure water consumption against the cows’ daily needs. Fifty gallons per cow per day of drinking water is a reasonable estimate to cover the high and low points in the daily routine, he says. There should be a minimum of two waterers per group or pen. Cows shouldn’t have to walk more than 50 feet to a waterer. Often, lack of adequate water supply is related to over-stocking in group-housing areas, and lack of enough time and space allocation for every cow in the group, whether in free-stall barns or loose housing, he says.

In assessing whether there are anti-quality factors, Beede suggests having water samples analyzed periodically by a reputable laboratory. “Thirty to $40 will give you a very good water analysis at a certified lab,” he says. “It’s a relatively inexpensive thing to do.”

View the procedures for sampling.

In 2003, a group of researchers at the Zinpro Corp. surveyed more than 3,600 water samples at livestock farms across the U.S. and found between 15 to 30 percent of the samples exceeded upper-desired levels for calcium, sodium and sulfate, while more than 40 percent exceeded upper-desired levels for iron and manganese.

A lot of people have said that high-iron water is not palatable to cows, but there isn’t a lot of data to back it up. Beede and other researchers at Michigan State University did conduct an experiment to find some answers. They set up a series of water tubs cafeteria-style, so they could see which tubs the cows preferred based on iron concentrations in the water. They found that iron concentrations of 4 parts per million did not affect water intake (compared to controls) but 8 parts per million did. Many farms exceed this critical threshold.