Water is the nutrient needed in the greatest quantity — much more so than other nutrients such as protein and energy. When a calf is born, its body content is around 70% water. Provision of drinking water immediately after birth improves growth and development of calves pre- and postweaning, potentially by stimulating rumen development, thus increasing nutrient availability. A calf’s water intake typically increases with size and age, with the greatest increase occurring at weaning. Calves struggling with health challenges often have both low starter grain and water intake. We are very careful not to limit water availability to lactating cows, dry cows and heifers, but pre-weaned calves seem to be often overlooked in respect to water requirements.
Provide Clean, Fresh Water at all Times
Water from milk or milk replacer isn't going to be sufficient to encourage starter intake- there is just not enough water.
Water intake in calves less than 1 week old is modest but significant, averaging 0.5 gallon (2 liters) and increasing steadily to 1.2 gallons (4.5 liters) by Day 49.
Calves receiving water from birth tended to have lower scours scores, and greater body lengths and hip heights after weaning, compared to the calves receiving drinking water later.
Calves need four times more water than dry matter intake — a 4:1 ratio (A.F. Kertz).
Weight gain between birth and 4 weeks of age was reduced by 38% and starter intake by 31% for calves that did not receive supplemental water in addition to their milk replacer (A.F. Kertz).
Water Quality is also Important
Calves prefer to drink clean water. Test water sources for bacteria and mineral content.
Keep water buckets free from environmental contamination - dirt, feed, manure, algae. If the water is dirty, calves will drink less water and eat less.
Utah State University found increased daily gains and weaning weights when water buckets were dumped and rinsed daily compared to weekly or every 14 days.
When possible, place water and grain buckets as far apart as practical in individual pens, or have a divider.
Calves will dribble water into the starter and starter into the water. This makes for wet starter and dirty water, which will lead calves to consume less of both.
Temperature Plays a very Critical Role in Water Intake
Calves like warm water, especially in the wintertime. Calves will not need to use additional energy to warm colder water to their rumen temperature.
Younger calves prefer to drink water closer to body temperature 103°F ( 39°C) compared to well-water temperature (50°F/ 10°C).
Calves cannot drink ice! In freezing situations offer body-temperature water.
Calves attempt to maintain body temperature in the summer months - increased respiration and sweating results in water losses which have to be replaced.
During periods of Heat Stress the Upper Critical Temperature (UCT) for calves has been shown to be 78°F (25°C) or greater.
Water Plays an Essential Role in Rumen Development
Milk is about 87% water. Calf starter grain is usually 10% moisture.
When a calf drinks water, the water goes into the rumen, as does the starter feed.
Milk by-passes the rumen via the esophageal groove, and is deposited into the abomasum of the calf.
Water in the rumen provides a medium for ruminal bacteria to live in. To ferment grain and hay, rumen bacteria must live in water. Without water ruminal development is slowed.
If calves don't drink enough water, they won't consume enough calf starter. That means calves will grow slower, and their rumens won't be able to perform as efficiently when they make the transition to a ruminant diet.