When temperatures are high, daily water consumption can increase from 15 to 40 gallons per cow. Dairy cows require approximately 3-4 pounds of water for each pound of milk produced.
Factors limiting water intake include a high salt content, high iron or sulfur, and stagnation.
Some blue green algae are even toxic. Placing a small water tank in a corner of the holding pen has increased milk production 2 to 4 pounds per cow. Shade the water tank. Shade Properly constructed and maintained shades are effective in reducing heat stress. Shades should be a minimum of 10 feet high and no more than 30 feet wide to allow for drying underneath.