Drinking water for dairy cattle: Part 2

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In the first article of this series we noted the importance of water in dairy cattle rations. By weight, water is the most important nutrient in a milking cow’s ration easily making up greater than 80% of the ration’s total weight. The previous article focused on the chemical and mineral composition of dairy cattle drinking water. Hopefully that article motivated you to have your farm’s drinking water tested for the constituents most often leading to water quality issues: total dissolved solids (TDS), sulfate (SO4), chloride (Cl), iron (Fe) and nitrate-nitrogen (NO3-N).

In our previous article we suggested that further water testing and/or treatment should be considered if the above named constituents are greater than acceptable levels (see Table 1), because at these higher levels these constituents may negatively affect animal health and/or milk production, interfere with the germicidal activity of cleansers and sanitizers (e.g., chlorine) and cause problems with water system components (e.g., pipes and pumps). In fact, some water quality problems such as excess iron can lead to such poor animal performance (e.g., health problems, reduced milk production) that it can be a “business-breaker” (2). High levels of some constituents (e.g., iron, nitrate-nitrogen) can also endanger human health if people are drinking from that water source (1). If levels of these constituents reach “retest levels”; further testing is warranted and one should even consider sending multiple samples to multiple certified laboratories to confirm/deny whether these constituents are problematic. If on further testing a constituent reaches or exceeds “actionable levels” dairy producers should consider consulting professional water treatment options for their cattle’s drinking water.

Water treatment options vary somewhat depending on the water quality issue involved.  A major difficulty in treating drinking water on dairy farms is posed by the huge volumes of water involved. Recall that high producing dairy cows may consume up to, or even greater than, 50 gallons of water per day. Multiplying this use over hundreds, or thousands of cows, quickly results in a staggering daily volume of water requiring treatment. Thus, one of the best water “treatment” options may be finding an alternate water source that isn’t plagued with the offending constituent (2).

Water treatment options include distillation (too costly), reverse osmosis (RO), ion exchange resin system (traditional water softener employing salt), oxidation + filtration via aeration (often called an “iron curtain”) and hydrogen peroxide (H2O2) injection systems (2).

Removal of excess TDS and excess sulfate + chlorine usually employs traditional water softeners or RO systems. Reverse osmosis systems remove 80-90% of these constituents depending on their design. Conventional water softeners are effective, but are not designed to handle large volumes of water and require an acceptable place to dispose of the brine flush water needed to recharge the system. Depending on the number of animals served, it may be necessary to design a water treatment system in such a way that large volumes of “treated” water can be stored for use at times of peak demand (2).

Oxidation systems are mainly employed to remove excess iron from cattle drinking water. The “iron curtain” system employs aeration to convert the iron to a precipitate (Fe+3) which is then subsequently filtered from the water. The hydrogen peroxide (H2O2) system employs the Fenton Reaction which converts iron from Fe+2 (soluble in water) to Fe+3 (insoluble in water) and then filters out the Fe+3 as a precipitant. This system injects H2Ointo the drinking water (8 oz of 35% H2Oper 1,000 gallons of water). This system is quite cost effective. A suitable injection pump costs around $500 and the cost of 15 gallons of 35% H2O2 solution is around $100 (enough to treat ~240,000 gallons of water)(2).

When working with water treatment vendors it is absolutely essential they understand the following items about your farm’s situation (2):

1) Do they know how much water your dairy uses? More than likely, your dairy uses much more water per day than the typical water treatment professional is accustomed. I have put together a short paper, Estimating Water Usage on Dairy Farms, that helps producers understand the volumes of water needed on a modern dairy farm. The paper also has an accompanying spreadsheet that producers can use to estimate daily water needs on their operations. To get a copy of the paper and/or the spreadsheet, send me an e-mail request specifying your request.

2) What is the treatment rate (volume/time) of their system? Again, your dairy will most likely consume water, particularly at peak demand periods, with which typical water treatment professionals are unaccustomed. Can their systems keep up and provide enough treated water to meet your peak demand?

3) Does the water treatment provider guarantee their system will meet peak demand and reduce the undesirable constituent to acceptable levels? Will their system meet this requirement throughout the expected useful life of the system? Are they willing to provide such guarantees in writing?

4) What is the expected useful life of their system and what are their system’s maintenance requirements and costs? Who is responsible for maintenance—you or them? Do they offer a service contract, and if so, what does it cost and what does it cover?

5) What chemicals (e.g., other mineral elements) does their system/method add to the water and at what concentrations? They may add nothing, but some systems add significant amounts of constituents (e.g., chlorine) that may cause an entirely new set of problems.

6) Ask potential water treatment providers to allow you to contact other customers using their system. Visit these other installations of this provider’s system to determine whether their products, services and warranties are as good as advertised. Run from any water treatment provider not willing to provide you this information.

Caveat Emptor: “Buyer beware!” Unfortunately, the field of water treatment is filled with an abundance of people and companies willing to sell water treatment systems of every size, shape and treatment method, whether your water needs treatment or not, and whether their method actually works or not. For those wondering about the effectiveness of one or many of the supposed treatment methods an interesting and helpful website is available to untangle most of the wild and bold water treatment claims. It is entitled: “H20dot con: Water-related Pseudoscience Fantasy and Quackery” and is available here. The site was developed by Dr. Stephen Lower, a retired Chemistry professor at Simon Fraser University, in Vancouver, Canada. Dr. Lower developed and writes at the site to help consumers sort out which of the many water treatment methods actually have scientific merit and which ones are most likely hype and/or downright quackery.  Most water treatment methods offered to solve purported bad water problems in commercial dairy farms were first available and/or sold to homeowners and consumers. To quote from the website about Junk Science in the Market Place:

“Magnets and “catalysts” for softening water, magnetic laundry balls, waters that are “oxygenated,” “clustered,” “unclustered” or “vitalized” (purporting to improve cellular hydration, remove toxins, and repair DNA), high zeta potential colloids and vortex-treated waters to raise you energy levels, halt or reverse ageing and remove geopathic stress—- all of these wonders and more are being aggressively marketed via the Internet, radio infomercials, seminars, and by various purveyors of new-age nonsense. The hucksters who promote these largely worthless products weave a web of pseudoscientific hype guaranteed to dazzle and confuse the large segment of the public whose limited understanding of science makes them especially vulnerable to this kind of exploitation. The purpose of this site is to examine the credibility of these claims from the standpoint of our present-day knowledge of science. The latter, of course, is always evolving and is never complete, but it makes an excellent “B.S. filter” that is almost always reliable. It is hoped that the information presented here [at the web site] will help consumers make more informed decisions before offering up their credit cards to those in the business of flogging pseudoscience.”

Hopefully you are routinely sending water samples of your cow’s drinking water to a certified laboratory on a quarterly basis and maintaining a historical record of those analyses. If your water test results suggest that you may need to consult a professional water treatment company to rectify a problem, an appropriate closing message on water treatment methods would be, “Show me the science and the proof of improved cow health and performance before I show you five or six figures in George Washington’s finest dollars.” (1)

Next month we will have the final installment in this series. That article will address the important issue of “water delivery”; “Are you providing an ample supply of good quality, fresh, clean water to your cattle?” In that article we will detail the results of theThumb H2O Project’s measurement of whether the milking cow facilities on real dairy farms met guidelines insofar as waterer numbers, space, location, and cleanliness are concerned.

Table 1: Actionable levels of important water constituents (1, 2, 3).






Total Dissolved Solids (TDS)

>500 ppm


Sulfate (SO4), + Chloride (Cl)

>250 ppm

>500 ppm

Nitrate-nitrogen (NO3-N)

>10 ppm

>20 ppm

Iron (Fe)

>0.15 ppm

>0.3 ppm


<6.5 or >8.0

<6.5 or >8.5


1 Beede, D.K. 2004. Water Intake and Supply for Dairy Cattle. Michigan Dairy Review, Vol. 9, No. 3; July, 2004.

2 Beede, D. K. 2009. Solving Bad Water Problems for Thirsty Cows. Proc. Western Dairy Management Conf., Reno, NV (pdf filehttps://www.msu.edu/~beede/dairycattlewaterandnutrition.pdf).

3 Looper, M.L. and D.N. Waldner. 2007. Water for Dairy Cattle. Oklahoma Cooperative Extension Service, ANSI-4275.

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