Water, the Forgotten Nutrient?

By Dr. John Yost

I have a riddle for you. If you have too much, or too little, you worry about it constantly but if you have the right amount you don’t think about it.

The answer is water.

We understand that water is the single most important nutrient to sustain life, yet most of the time we take it for granted. After all, have you ever been standing in front of the kitchen sink, watching your neighbor get a rain shower that you wish would move a half mile to the north to help your crops out? Our crops in the field don’t care about the quality of the water, as long as they get it. For our livestock, water availability and quality are crucial to their health and performance.

There are several factors that determine how much water cattle will need to consume. A cow’s body is estimated to be comprised of 58% to 81% water. If she is lactating, her milk is about 87% water. The volume of free water that needs to be available per head is dependent on several factors. Their mature body weight, the amount of dry matter consumed, ambient temperature and relative humidity, production level, the temperature and quality of the water all affect their consumption. In general, it is estimated that beef cattle require one gallon of water per 100 pounds of body weight. The estimation can double for lactating cows, and as environmental temperatures reach 90 degrees for all production classes, to allow 2 gallons of water per 100 pounds of body weight (Oklahoma St. Univ. Extension Publication e-974).

As you consider supplying your herd’s water needs, you need to factor in their housing environment and behavior. Spring forages can be 80% moisture, and supply about 0.5 gallons of water for every pound of forage dry matter consumed. As forages mature their moisture content drops significantly, and more free water will need to be made available. Cattle are estimated to drink 2 to 5 times each day, for 1 to 4 minutes at each visit, consuming about 2 gallons of water per minute.