Abundant, high-quality drinking water is the most essential nutrient for dairy cattle. Typically, water is a relatively inexpensive and abundant resource in most dairy operations.
However, if water quantity or quality is a problem, then dairy cows, dairy farmers and their nutritionists have big problems to maximize productivity and health.
Dr. David Beede, Department of Animal Science, Michigan State University, addressed the issue during one of the seminars at World Dairy Expo last week.
“Often dairy farmers and nutritionists do not consider two major aspects of adequacy of water nutrition: how much are cattle drinking and what is the quality of the water consumed?” he said.
Beede presented the findings from a survey in which researchers looked at 3,600 water samples in livestock farms. He said 15-30 percent of total samples exceeded the upper threshold concentrations for calcium, sodium and sulfate. Iron and manganese concentrations exceeded desired thresholds in over 40 percent of the samples.
“Based on my 45-year experience, the most common water quality problems are excess iron, sulfate and chloride that can affect cow health and performance," he said.
Beede emphasized that nitrates in the water can affect reproduction performance, and sulfate can cause diarrhea, dehydration and fluid loss, especially in young calves and fresh cows. He urged producers to consider having water samples analyzed periodically by a reputable laboratory.
“If water quality problems are identified, the challenge is to either find an alternate water source (drill a new well or hook up to another source) or use an effective water treatment system,” he said.
Solutions to consider
Beede offered examples of solutions, noting the pros and cons of each.
He suggested water treatment by hydrogen peroxide, chlorination or ozonation and removal with a mechanical filtration of iron (and manganese). For excess sulfate or chloride, an alternate water source or reverse osmosis are the most common and effective approaches for removal.
Hydrogen peroxide also kills microbes, he said. Chlorination is similar to how swimming pools and municipal water systems are treated, but he said because chlorine has a longer life cycle than hydrogen peroxide, it can also kill the beneficial microbes in the cow’s rumen.
Beede mentioned studies looking at how the taste of water affects water intake by cows and calves. The animals were offered water in several pails, and each pail had a different concentration of iron in the water.
“We learned that cows and calves prefer a certain type of water, and that will affect their willingness to drink," he said. "In the studies, calves and cows drank from the pails with water that was low in iron. As the iron in the water increased, they did not choose to drink from that pail.
“If a calf drinks less water, dehydration is more likely to occur, and then they won’t eat as much, so their rate of gain will decrease.”
A key point in water treatment, according to Beede, is knowing how much water must be treated daily. Fifty gallons of drinking water per cow per day is a reasonable estimate to accommodate extremes of daily water use.
If treated water is used for other purposes, such as a milking parlor or milk house, this must be included in calculating the daily water needs.
When water quality is not an issue, the most common water nutrition problems in most dairies are not providing enough watering stations, enough space at watering stations and/or water receptacles that do not fill quickly enough when animals are drinking, which means there are not enough uninhibited drinking opportunities for each animal during her normal daily routine.