How many gallons of water a day do Holstein cattle drink?

Answer 1

This is all too highly dependent on many other factors including air humidity, air temperature, diet, stress, whether that cow is lactating or not, reproductive demands and physiological demands. As such no definite answer can be obtained, simply because people tend to grossly overestimate (more that than underestimate) the amount of water a cow drinks per day.

The common "fact" spreading around via the media is that a Holstein (or the "average cow") will drink a bathtub full of water every day, but that in itself is misleading because it depends on the size of the bathtub and how full would be considered full for that bath tub!! Thus the answer to this question still remains as "It depends."