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Virginia Cooperative Extension - Knowledge for the CommonWealth

Would You Drink The Water?

Dairy Pipeline: September 2008

Bob James, Extension Dairy Scientist, Dairy Nutrition
(540) 231-4770;

During a time of high ration cost with little likelihood of relief, we begin to look for those practices to improve performance but not add to the expense of producing milk. One area frequently overlooked on dairies is availability and quality of water for the dairy herd.

Seventy to 97% of total water intake of dairy cattle comes from drinking water with the remainder arising from feed intake. There is a strong relationship between water intake and total ration dry matter intake. A good rule of thumb is that cows should consume 4 – 5 lb. of water (about three quarts) for each lb. of dry matter intake or about 3 lb. of water for each lb. of milk yield. Cows will consume the majority of their water immediately following milking. Common guidelines state that there should be enough trough space so that half of the cows have at least 2 ft. of space when exiting the parlor. Provide at least two water sources for each group cows and remember that cows should never have to walk more than 50 ft. to get a drink. Sources should be protected from sunlight as well. Shallow water receptacles (less than 12”) are desired because they prevent stagnant water and are easier to clean.

Assuming that water is available, what’s the quality? The most common water quality problem is with fecal and feed contamination. Water sources located adjacent to feed bunks or placed too low are commonly loaded with manure and spoiled feed. This water is frequently unpalatable and may contain high levels of undesirable bacteria. The quickest “fix” is to drain and clean waterers on a daily basis. This practice should be done daily or at least every other day on each water source for the lactating and dry cow herd. Most recently manufactured waters have large drain holes or may be dumped readily. In the case of concrete water tanks, consider drilling large drain holes near the bottom and devising stoppers which can be routinely removed with little effort. If this is not possible the tanks should be replaced. Finally water should meet similar standards as for human consumption. Test water to determine total dissolved solids (<500ppm), paying special attention to levels of sodium (<150 ppm), chloride (<250ppm), iron (.3 ppm) and manganese (.05ppm_). Nitrate contamination is of particular concern as well and should be less than 20 ppm as nitrate – nitrogen.

Granted fine tuning the ration is important, but the first step to achieving improved performance should be directed towards better management of water intake for the dairy herd. Would you drink the water?

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