Feeding milk replacer or whole milk does not provide enough water for growing pre-weaned dairy calves.
Young calves have a natural requirement for water which is often higher and separate than what is provided by most milk-based feeding programs. By providing all the water needed, calves adapt to dry calf starter quicker, grow faster and ideally can be weaned at an earlier age and at heavier weights. I recommend clean, good-quality water should be made available at all times in addition to their whole milk or milk replacer diets.
The daily water intake by an average pre-weaned dairy calf is roughly 10 per cent of its bodyweight. The actual amount of water drunk depends upon a host of factors such as calf age, diet, health status, stress level, type of housing, sanitation, environment and water quality.
For example, a 90-lb. dairy calf housed outside in a hutch and sunning itself at comfortable temperature of 10 C and 65 per cent humidity requires about four litres of clean water (re: 90 lbs. x 10% / 2.2).
As a dairy nutritionist, I know more milk replacer (or whole milk) is needed solely to meet the basic water requirement of pre-weaned calves than recommended by many conventional milk feeding programs. I know of many dairy producers who feed a maximum of four to six litres of milk replacer per day (plus supplemental calf starter) without extra water until weaning. In theory they could raise better-growing calves without changes to their feeding program, if only they would provide extra water on a free-choice basis.
Case-in-point: A 1999-2000 research study conducted at the APC Calf Research Unit in Ames, Iowa tested water consumption in 120 newborn Holstein bull calves. The researchers offered “extra water” to each calf on a daily basis in addition to about four litres/day of a milk replacer diet.
They reported many consistent results that demonstrates the importance of extra water made available for pre-weaned calves. Highlights of their findings include:
- The “total water” (milk replacer plus extra water) balances out to about six to eight litres consumed by each pre-weaned calf per day; the more liquids fed by milk replacer means less “extra water” is drunk and the vice versa is also true. One can assume the calves’ total water requirement to maintain life-giving functions are achieved.
- Water consumption is very much correlated with dry calf starter intake. These researchers stated that increased daily starter intake accounted for more than 60 per cent of the variation recorded in increased water intake. According to Penn State University; as soon as a young calf readily accepts dry calf starter, its rumen development is accelerated, which leads to superior growth rates and promotes early weaning.
- Natural water consumption among calves varies greatly. The actual amount of total water required by each dairy calf differs, because of the large number of factors associated with the need for water.
Dairy producers should also practice good water hygiene by regular cleaning of all buckets or troughs for young dairy calves. One Utah State University field trial recorded a nine per cent better growth rate in pre-weaned calves drinking from pails that were cleaned every day as opposed to cleaned every two weeks.
Similarly, algae growth tends to be a summer problem that can be alleviated by a daily scrubbing of calf pails, troughs and any drinking devices.
Given the chance, pre-weaned calves may drink a lot of clean water in addition to their whole milk or milk replacer diet. However, satisfying this thirst also promotes good dry calf starter intake, which in turn encourages good rumen development and may advance their age of weaning. When good-growing dairy calves are not bawling for more water, they are off to a good start and they might just become the most profitable cows on the dairy farm.