A recent public meeting about a proposed dairy expansion in Wisconsin included the usual queries about odor, water quality and manure management. However, it also featured a question that’s cropped up with increasing frequency: “How much water is the dairy going to use and will it affect my (neighboring) well?”
The issue of water usage has graduated from a regional issue in the arid west, where it remains a significant concern, to one that potentially affects dairies from coast to coast — especially as dairies increase in size. No longer do you need to solely focus on how much water you must have to ensure an adequate water supply for your herd; you must also contemplate how your water use affects your neighbors.
Here’s what you need to know about the latest trends and research regarding water use on dairies.
Reduce, re-use, recycle
Like most dairies, Sierra Vista Dairy in central California wrings as much as possible from every drop of its well water. In the midst of a severe water crisis, water use in California receives lots of attention these days as surface water is being shifted away from agriculture for urban needs.
“Water (on this dairy) is used two, three or more times before it’s used to irrigate crops,” says Wes Nelson, dairy manager. For example, as on many operations, water from the plate cooler is used to flush the parlor and then to flush the free-stalls.
Dairies have honed their water efficiency and recycling skills for years. As a result, modern dairy farms use only 35 percent of the water required to produce the same amount of milk that they did in 1944, according to Cornell University research published in the JuneJournal of Animal Science.
The efficiency of water use on dairies is amazing, says Todd Bilby, Texas AgriLife extension dairy specialist. “Consumers need to keep in mind that most of the water that actually leaves a dairy (and not recycled) leaves in the form of an edible product — milk.”
Not diverting water
Still, perceptions persist that dairies must be using lots of water, possibly diverting it from other uses.
For example, to find out if West Texas dairies drew more than their share of water from the environmentally sensitive Ogallala Aquifer, Texas and New Mexico dairy extension specialists recently calculated daily water needs for cows, dry-cows, heifers and facility cleanup.
They estimated that a typical 2,000-cow dairy in the area sits on 160 acres, milks three times daily, does not have wash pens, and uses minimal water for cow-prep procedures. The researchers concluded that under these assumptions, the dairy would use about 123 acre-feet of water annually or 9.25 acre-inches per acre per year. (An acre-foot is about 326,000 gallons, or about enough water to cover a football field approximately 1-foot deep.)
Meanwhile, cotton crops drink 12 inches of water per acre per year; wheat production requires 15 inches per acre per year, and corn needs 22 inches per acre per year.
The dairy, in this case, uses less water — on an inches-per-acre-per-year basis — than the crops do, but it really not a matter of saying one is right and the others are wrong.
“We’re all in agriculture together,” says Bilby. “We don’t need to be fighting amongst ourselves, but need to work together. Dairies provide a niche market for crop producers and dairies need the feed produced by crop farmers.”
More research under way
If there is a silver lining, it’s the fact we are paying closer attention to how much water cows actually need.
Using water meters, a two-year study on a northwest Ohio dairy found that the average cow used 29.9 gallons of water per day. If you add in water included in the ration, consumption reached as high as 39.8 gallons per day.
The cows on the farm studied averaged 80 pounds of milk daily, meaning it took about 4.5 gallons of water for each gallon of milk produced — at the use rate of 29.9 gallons of water per day.
Meanwhile, USDA’s Agricultural Research Service is beginning a new study on dairy groundwater use in Idaho. At issue are differing estimates of dairy cow water needs used to develop a mitigation plan for several Magic Valley wells and their impact on aquaculture in the area.
At press time, negotiations were under way regarding the possible shut-off of wells used by dairies and businesses in Idaho’s Magic Valley.
Currently, six dairies have signed onto the project, which is expected to be completed by the end of next year. Researchers would like to add another six operations.
“We’re just getting started,” says Dave Bjorneberg, Northwest Irrigation and Soils Research Laboratory director. “But our aim is to measure the amount of groundwater pumped, as well as measure the amount for wastewater produced, to give the net consumptive water use on a per-cow basis for each farm.”
If you’re using water to irrigate crops and the wells are shut off, you lose that crop year, which is bad enough,” Bjorneberg explains. “But you can’t go without water on a dairy. Hopefully this research will help dairymen, farmers and others to have a plan for how to deal with water rights in the future.”
At the end of the day, knowing how much water you use comes in handy for a variety of reasons, no matter where you live. For more resources on calculating water needs and water-use tabulations, go to: www.dairyherd.com/management
California groundwater concerns
A new report by the U.S. Geological Survey shows that the current drought, combined with groundwater pumping, is causing problems for the San Joaquin Valley aquifer, especially in the southern part of the valley. This situation could make water use even dicier in the future.
To read the full USGS report, go to: www.dairyherd.com/environment
Keep tabs on groundwater draws
Even in areas where water is abundant, farmers are increasingly asked to keep tabs on groundwater draws.
For example, in Pennsylvania, if you draw more than 10,000 gallons of water a day, you must report this use to state authorities. This purely a reporting requirement, with no regulations attached.
In Michigan, the mandatory reporting requirement jumps to operations that use 100,000 gallons of water a day. “That equates to dairies with about 300 cows or more,” explains Scott Piggott, manager of Michigan Farm Bureau’s ecology department. In addition to reporting requirements, Michigan has implemented a Web-based water withdrawal assessment tool to help new water users with greater than 100,000 withdrawal capacities determine if their use will adversely impact natural resources.
The tool and related process is based on 28 years of data on fish habitat and is designed to protect streams from large water withdrawals.
“We have a lot of water in Michigan,” he adds. “Of course, there are pockets where groundwater is hard to come by, but we expect Michigan agribusiness to be able to use our abundant water to continue to grow. We expect 90 percent or more of new uses in all sectors to move forward without permitting.”