Cows need a minimum of 12 gallons of water daily. Dairy cows need up to 30 gallons of water per day. Cows can get part of their water through lush forage, but they also need drinking water.
Cows depend on drinking water to maintain proper body temperature. When temperatures rise to 95 degrees Fahrenheit, cows need 2 ? times as much water as they do when the temperature is 70 degrees. Lactating cows need extra water to maintain milk production. If cows do not get enough water, they can develop heat stress. Thirsty cows are also more likely to drink from ponds with dangerous concentrations of salt or algae.