Our large dairy cows must consume huge amounts of water to survive, stay healthy and be productive. High producing cows will consume 30 gallons or more per day in conditions with mild temperatures and low humidity. In hot and humid conditions, they will need 50 gallons of water per day.

Lactating dairy cows require 4.5 to 5 pounds of water per pound of milk produced. This equates to roughly one-half gallon of water for every pound of milk produced. Even a small limitation in water intake will decrease dry matter intake by 1 to 2 pounds daily, which can limit peak milk production by 2 to 5 pounds – directly affecting dairy profitability.

Dairy farmers spend much of their time focusing on feeding their cows correctly. Feedstuffs – forages, grains and commodity by-products – are routinely analyzed for their nutritional content. Complex computer software can quickly formulate diets for any level of milk production.

Photo courtesy: urbancow/istock

Focusing on all needed nutrients

Given the proper information, dairy farmers and nutritionists can know in a matter of seconds the perfect combination of feed ingredients that will maximize milk production or growth rates and, most importantly, how much it will cost. Amazingly all this time and energy is spent on dozens of feed ingredients – the vitamins, the minerals, the protein and the energy – but the word “water” – the most important nutrient of all – is seldom mentioned in the discussion of a dairy cow diet. Ironically, dairy farmers often do not know how much water their herd should consume or the quality of that water.

A herd of 100 cows requires 2,000 to as much as 5,000 gallons of water to quench the herd’s thirst every day. That means a 100-cow herd will consume the water in a 20- by 4-foot swimming pool about every two days. It’s critical – a matter of life and death – that on every dairy farm there’s a reliable, consistent source of uncontaminated water that’s supplied continually to every cow, heifer and calf on the property. Fortunately the moisture contained within feedstuffs also counts for cows’ and heifers’ water requirements.

One study suggests that up to a third of a cow’s water needs can be satisfied through the moisture content within the diet. For example, if a cow eats 100 pounds of feed per day and the moisture content of the diet is 50 percent, the cow is consuming 50 pounds or about 6 gallons of water.

Taking care of water needs

Cows don’t need a lot of time to drink water. One study showed that cows can do all their drinking in about 30 minutes throughout the day. However, when they do need to drink there should be lots of water available. When given the opportunity, cows tend to alternately consume feed and drink water. Ideally, fresh, clean water should be available to the cow whenever she consumes feed. So making access to water easy for cows and heifers is important in making sure they get enough water to drink during the day.

Throughout the dairy and near the feeding areas, cows should have unrestricted access to waterers or water troughs. Cows are known to also like water soon after they have been milked; so there should be access to water near the exits of milking parlors. Watering troughs should be large enough to allow a number of cows to drink at the same time without crowding. Watering troughs should be cleaned routinely. In regions of the country where water freezes during winter it’s important to keep water free of ice so that drinking is not limited in the cold environment. Studies on the ideal temperature of water for dairy cows are inconclusive.

Water is necessary in a wide array of bodily functions at both the extracellular and intracellular levels. Key roles include physiological maintenance such as electrolyte balance, osmotic regulation and thermoregulation. Water is necessary for the excretion of urine and feces as well as growth, pregnancy and lactation. Water is necessary for proper rumen function and digestion.

Water with excessive solids from dirt can hinder cows’ desire to drink. Solids and minerals that are present in water may interfere with proper vitamin and mineral metabolism. Water with high levels of sulfates, iron, manganese or nitrates may be especially problematic with cow health and milk production. Particularly in close-up dry cow diets where the anionic balance is critical for proper calcium uptake at the time of freshening, excessive levels of some sulfates or chlorides may result in diets that are overly anionic.

Water is the most important nutrient for all forms of life.Photo courtesy: Ulrich Knaupe/istock

Monitor pH level

Water is necessary for the transfer of minerals between cells and the maintaining of the proper acid/base balance in the body. It’s important to monitor the pH level of the drinking water for dairy herds, as well. Many metabolic functions such as the synthesis of proteins or the transfer of vitamins are sensitive to the acid/base balance at the cellular level. Water with a pH less than 5.5 (acidic) may increase problems related to mild rumen acidosis. Alkaline water (pH greater than 8.5) may result in problems related to mild alkalosis such as amino acid and B-vitamin deficiencies. When cows are drinking alkaline water, rations high in alfalfa, buffers and minerals can contribute to mild alkalosis.

However, water that’s contaminated with pollutants or is high in antagonistic minerals can be just as problematic as not getting enough water.

Common signs of poor water quality and intake include depressed feed intakes, which leads to depressed milk production. Poor water quality may result in depressed immune function leading to poor conception and/or abortions. Digestive upsets resulting in diarrhea in cows or scours in calves can be caused by contaminated water. If water sources cause digestive upsets in humans, there’s a good chance that the water is not well suited for animals, either. Water should be tested annually for bacteria such as coliform along with pH, dissolved solids and minerals.

The economic implications of water consumption and water quality are often overlooked on dairy farms. The availability and importance of water should not be taken for granted. Not having enough water or settling for poor quality water can be a costly mistake.

Cover photo mtreasure/istock