Next to oxygen, water is probably the most important nutrient for dairy cattle. University of Illinois research suggests the water requirement of a high-producing dairy cow is greater than any other land-based creature due to milk being 87 percent water. Additionally, water is essential for maintenance of fluid and heat balancing, circulation of nutrients, and excretion of urine, feces, and respiration. This adds up to as much as 80 percent of total body water needed for the lactating cow. While producers carefully consider the nutrients and protein levels in the animal’s ration, often very little thought is devoted to the importance of providing clean, free-choice drinking water. For every gallon of milk produced, four gallons of water is required. A gallon of water weighs approximately 8.3 pounds while a gallon of milk weighs approximately 8.6 pounds. As a rule of thumb, a cow producing 80 pounds of milk will require approximately 37 gallons of water. During the heat of summer, that requirement may increase an additional 20 percent.
During times of low milk prices,
producers will often feed less ration in an attempt to lower feed costs. While it’s always important to closely monitor production costs, milk prices will still be above feed costs. Never has there been a better time to ensure proper water intake and availability. Water will always be the lowest cost nutrient. Use the information below as a guide to ensure you are providing proper water supply:
• Provide no less than one foot of linear trough space per cow in return alleys and breezeways off of the milk parlor. It is normal and typical for cows to drink a lot of water of water immediately after milking. Penn State University data suggests that enough water trough space should be provided to allow half of the number of animals in the parlor to have two feet of linear trough space per cow upon exit of the parlor. For example, if the parlor is a double-10, there should be approximately 20 feet of linear trough space.
• Ensure at least two water sources per group where cows are housed. Cows shouldn’t need to walk more than 50 feet for water. Also, water should be in close proximity to the feed bunk and should be protected from sunlight.
• Be sure to provide open space around water sources. Crossover alleys in free-stall barns should allow a minimum width of 13 to 14 feet, which will allow one foot for the width of the water trough and about five feet for other cows to pass behind cows that are drinking.
• Maintain head clearance around the water source — no less than two feet on each side. Less space may reduce optimal water consumption.
• Understand the filling capacity of
watering sources. Cows should never have to wait for water.
• Keep water clean. Water sources should be routinely (daily or weekly) cleaned. Dirty water is unacceptable.