The Importance of Water in Dairy Cattle

Next to oxygen, water is the most important nutrient for dairy cattle.  Studies from the University of Illinois suggest water requirement of a high-producing dairy cow is greater than any other land-based creature due to milk being 87% water.  Additionally, water is essential for the maintenance of fluid and heat balancing, circulation of nutrients, and excretion of urine, feces and, respiration.  This adds up to as much as 80% of total body water for the lactating cow.  Intense care is logically given to specific nutrients in the ration, but the provision of clean, free choice drinking water receives considerably less respect.  For every gallon of milk produced, four gallons of water are required.  A gallon of water weighs approximately 8.3 lbs. while a gallon of milk weighs approximately 8.6 lbs.  Thus, as a rule of thumb, if a cow is producing 80 lbs. of milk, she will require approximately 37 gallons of water and an additional 20% more during the summer heat.
During times of low milk price, many rations will be cut to reduce feed costs.  While scrutiny of rations should always be practiced, milk prices will still be above feed costs.  Never has there been a better time than now to ensure proper water intake and availability.  Water generally will always be the lowest cost nutrient.
Use the below as a guide in evaluating proper water supply:

• Provide no less than one (1) ft. of linear trough space per cow in return alleys/ breezeways off of milk parlor. It is normal for cows to drink volumes of water immediately after milking.  Penn State University suggests enough water trough space to allow half of in parlor to be provided with two (2) ft. of linear trough space per cow upon exit of the parlor. This would mean if the parlor is a double-10, approximately 20 ft. of linear trough space.
• It is superior to provide 2 water sources per group where cows are housed. Cows shouldn’t need to walk more than 50 ft. for water. Also, water should be in close proximity to the feed bunk and should be protected from sunlight.
• Providing open space around the water is important. Crossover alleys in free-stall barns should allow a minimum width of 13 - 14 ft. to allow 1 ft. for the width of the water trough and allow about 5 ft. for other cows to pass behind cows that are drinking.
• Head clearance around the water source should be no less than 2 ft. on every side - less may reduce optimal water consumption.
• Understand the filling capacity of the watering source.   Cows should never have to wait for water.
• Water MUST be clean.  Water sources should be cleaned daily or weekly.  Dirty water is unacceptable.

For more information on how you can give your livestock exactly what they need, reach out to your local Co-op. For more content like this check out the latest issue of The Cooperator.