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Clean water: Essential to your dairy farm

Rachael Denhollander Published on 31 October 2013

In light of the fact that dairy cattle can survive up to 60 days without food, yet barely a week if deprived of water, the importance of clean water sources on a dairy farm will come as no surprise.

The details of what it means to “have clean water,” however, may hold some surprises even for veteran farmers.



Recent research has found that clean water is not only important but critical. Relatively minimal reductions of water intake, or low levels of certain contaminants in the water, will decrease livestock performance more quickly and more dramatically than any other nutrient deficiency.

Extensive research has led Michigan State University professor David Beede, one of the foremost experts on dairy cattle, to maintain that clean water is “the most important essential nutrient supplied to dairy cattle.”

Clean water is additionally vital to protecting human health through protecting herd well-being and assisting in thorough farm sanitation, making clean water sources vital to all aspects of farming.

Herd health and productivity
The importance of clean water is best understood in light of the functions that water performs for dairy cattle in producing milk, preventing illness and regulating basic cellular and organ operations.

Clean water is essential for milk production
While milk is packed full of nutrients and healthy fats, the vast majority of milk (87 percent) is nothing more than water. For this reason alone, the amount of milk a cow produces is directly related to how much water is in a cow’s body – the more a cow drinks, the more milk they can produce.


Similarly, the caloric demand on a lactating cow’s body is significant, causing milk production to be directly tied to how much nutrition a cow is able to consume.

However, because a cow’s food intake is reduced in the event of even minimal dehydration, poor water consumption will decrease milk production not only due to lack of available fluids to produce milk but also lack of available calories to fuel lactation.

Finally, a cow’s overall well-being also has direct implications on milk production. A cow struggling with illness or with minimally compromised health simply cannot produce the same amount of milk a healthy cow is capable of producing.

As a result, surprisingly small amounts of contaminants and bacteria in a dairy cow’s water source can cause decreased milk production, even when signs of illness are lacking.

Clean water is essential to prevent illness
Illness can pose a serious risk to dairy herds, particularly as water-borne contaminants can infect a herd rapidly and cause illness with very low percentages of contamination.

The most common impurities which pose a risk to cattle can be divided into five major categories: total dissolved solids (TDS), sulfates (SO4), chloride (CL), iron (Fe), nitrate-nitrogen (NO3–N) and micro-organisms.


TDS is a measurement of all the inorganic matter dissolved in water and directly affects the water’s salinity. Salinity, in turn, can cause an imbalance in a cow’s digestive and cellular functions, resulting in diarrhea and dehydration with TDS levels as low as 1,000 ppm.

Sulfates also pose a high risk of causing diarrhea in cattle, as well as reducing overall water intake due to an unpleasant taste. When combined with other contaminants, however, sulfates are known to cause not only chronic diarrhea and dehydration but also retained placentas and displaced abomasums in fresh cows.

Iron contamination can be incorrectly dismissed as causing nothing more than water with poor flavor, but in actuality, iron levels above 0.3 ppm can cause iron toxicity, causing a cow’s cell membranes to break down, resulting in a serious condition known as oxidative stress.

Oxidative stress, in turn, can result in retained placentas, mastitis, metritis, decreased absorption of vital minerals and overall depression of the cow’s immune system.

Water contaminated with nitrate-nitrogen poses perhaps the most serious risk to cattle, with even mild cases of poisoning at levels as low as 20 ppm causing long-term infertility, miscarriages, vitamin deficiencies, poor growth rates and overall poor health.

More serious poisoning reduces the oxygen-carrying capacity of hemoglobin, causing seizures and, in severe cases, asphyxiation.

Micro-organisms form the final classification of water contaminants. This category is understandably the broadest, ranging from toxic algae to pathogenic bacteria and parasites.

Depending on the micro-organism, infection and disease can result from a cow’s ingestion of a single cell, while infected cattle can shed millions of cells per ounce of feces, causing infections to become rapidly systemic.

Clean water is essential for organ and cell functions
Apart from the role water plays in milk production and preventing herd illness, plentiful sources of clean water are also essential to a cow’s basic bodily functions.

Water is necessary for the elimination of waste products, the regulation of blood osmotic pressure, the transportation of nutrients, hormones and other chemical messages within the body, and the regulation of body temperature and respiration.

Simply put, without plentiful intake of clean water, a cow’s body ceases functioning properly at a metabolic and cellular level, regardless of any outward signs of distress.

Human health and farm sanitation
While pathogens and contaminants can certainly cause illness in cattle, many pose an even greater risk to humans.

Studies have shown that dairy farmers and people working on dairy farms have nearly double the chance of contracting an infection from their herd, making herd health a vital component of reducing the risk to humans in close contact with dairy cattle.

Additionally, while pasteurization has drastically decreased occurrences of passing illnesses from cattle to milk consumers, the risk remains higher than many realize.

Screening of collected raw milk has repeatedly shown significant levels of bacterial contamination for a wide variety of pathogens highly dangerous to humans, putting the health of those who handle raw milk products at risk of infection.

This is noteworthy, as studies have found that improperly handled raw milk is responsible for nearly three times more hospitalizations than any other foodborne disease outbreak.

Pasteurization is largely effective at removing these pathogens, but recent studies of multiple dairy farms have found that milk which is highly contaminated before pasteurization will likely remain contaminated after pasteurization, putting the public in general at risk.

Thus, ensuring a clean source of drinking water is vital not only to preserving herd productivity and health, but also a critical component of protecting humans as well.

Finally, contaminated wash water poses a serious risk to dairy herds and farmers alike by interfering with the ability to properly disinfect and sterilize equipment and surfaces on the farm.

Water high in iron, for example, has been found to interfere with the effectiveness of cleaning a farm’s watering system, allowing pathogenic bacteria to build up in the system and infect cattle.

Pathogen-laden water used for washing is also a significant hazard for the simple reason that contaminated water is incapable of disinfecting critical components of a dairy farm, such as milking machines and surfaces in contact with cattle, thereby allowing bacteria to flourish and infect both cattle and humans.

Science is confirming what veteran farmers have known for decades: Unrestricted and plentiful sources of truly clean water are vital components to all aspects of successful dairy farming, not only for increasing productivity and preventing illness in the herd, but for protecting human health and facilitating proper sanitary procedures.

There may be many different techniques and preferences in the farming industry, but there is at least one constant: Clean water is nonnegotiable on any farm. PD

Rachael Denhollander is a research analyst with Water 4 Dairy Inc. She can be reached by email .

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