Availability and quality of water
In terms of water availability, at least two water points should be present per group of cows. This will prevent dominant cows from monopolizing a single water point. You need to allow for 10 to 15% of a herd to drink at the same time, a minimum of 3.9 ft trough perimeter needs to be accessible per 20 cows for open surface water tanks to achieve this. The optimal height of the water trough is around 23.6-27.5 inches, and the water depth 2.75 inches or more, which allows animals to submerge their muzzle.
Water must be of excellent quality to ensure cows drink a sufficient amount. Therefore water quality should be checked regularly; this is especially true during warmer days. Water troughs should be cleaned daily to prevent bacterial growth. Often barriers are placed around water, or drinking troughs can be more than 3.28 feet in height to prevent cows from defecating into them. However these interventions can actually prevent the cows from drinking sufficient volumes. The only suitable way to prevent manure in the water troughs is to provide ample space around them. Passages with open water troughs should measure at least 13 feet wide to allow cows to pass while other animals are drinking.
Inadequate water supply or water of bad quality results in production losses, reduces overall resistance to disease and occasionally leads to outbreaks of disease. For optimal water consumption, water temperature should be between 50 and 68º F. The use of a precooler cools down the milk and can consequently heat up the drinking water, which is then piped to troughs raising the water temperature to the optimum temperature bracket for the cows during the colder winter days.
Heat stress and water consumption
Especially during hot summer days when animals suffer from heat stress, water consumption among cows may rise drastically by a factor 1.2 to 2. So a 50 kg yielding cow may drink between 250 to 350 liters of water when temperatures reach 80ºF. To allow cows to consume these large amounts of water, extra water points are needed when temperatures rise.