Dairy Excel: Water is the most valuable nutrient. Are your cows getting enough?


As I write this article, we are in the midst of the hottest week so far during the 2011 summer. The heat index (temperature and humidity) are reaching record levels. So, it seems natural for water to be a focal point for consideration on the management of our dairy farms.

We need to mind our P’s and Q’s relative to water for the animals. It is uncertain exactly where this cliche, P’s and Q’s, came from, but its meaning is widely accepted — to “mind your manners” or to “be on your best behavior.” Thus, we need to be on our best behavior in the management of the water supply for dairy cattle during the summer.

Keep close watch

Performance of animals needs to be closely monitored during heavy stress times.

Milk production and weight gain are highly dependent on water intake. Milk yield will rapidly decrease with limited water supply. Health state of animals can decrease very rapidly when water intake is limited, whether this is caused by lack of availability or the animal’s intake is depressed.

Animals need to have water available at all times, including pre-weaned calves, weaned calves, heifers, cows, and downer cows.

The animal’s body is generally 60 to 80 percent water, with the younger animal having the highest water content.

Dehydration can occur very rapidly; watch for a change in more firm feces; animals straining to urinate with low urine output; pinch the skin or eyelid and release — if it stays tented, then the animal is likely dehydrated; and monitor milk yield and gain.

Enough waterers?

Position of the water source is important. If you don’t have a water tank in the return alley, then now is the time to install one. Cows are withheld from water while in the holding pen, and the holding pen and parlor can be quite hot, so cows are eager to drink after milking.

Cool water from a plate cooler works well for this supply, but even if you don’t have a plate cooler, run a line to the tank from the main water source.

In the freestall barn, there needs to be about 2 linear feet of water space for every 20 cows. In long barns, waterers should be placed throughout the barn so cows don’t have to walk long distances to the parlor.

Also, observe traffic patterns around the waterers to identify if structural problems exist or if waterer space needs to be modified.

How much? Quantity of water supplied is important. Dairy cows need about 10 gallons a day just for maintaining their body and then about 0.35 gallons per pound of milk, so they can easily consume 40 gallons a day during the summer.

Not only is the total supply important, but check flow valves for proper operation. Improper flow rates can cause animals to stand longer at the waterer, they may give up and leave before consuming adequate water, or they may be pushed away may more aggressive animals waiting to drink.

At lower flows rates, space per animal even becomes more critical. Whenever possible, it is advisable to place a meter on the main water pipe so water usage can be monitored.

Pasture sources

For animals on pasture, water source needs to be checked regularly, especially since some springs are now either not running or are at reduced flow rates, and some surface water sources may be at low water levels.

Quality of the water must be monitored. Analytical information on the water source should already be known, but the water source may need to be re-analyzed if changes in composition are suspected or if the water source has changed.

Quality of surface water sources may especially change in the summer due to reduced water supply and more shallow depth facilitating more fungal growth.

Yep, you need to clean

Waterers need to be cleaned routinely, sometimes as often as daily in the summer. Bacterial growth, associated with feed particles dropped into the water, and fungal growth are rapid in the summer.

As nutritionists so often say “Water is the most valuable nutrient.” For the animals’ health and performance, a daily supply of clean, fresh water is needed.

So be on your best behavior in managing the water supply for your dairy cattle this summer. It will pay dividends — you can bank on it!

(The author is a professor and Extension dairy specialist at Ohio State University.)


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