Top 5 Ways to Maintain a Calf's Thermoneutral Zone

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Not familiar with thermoneutral zone (TNZ)? The TNZ of a calf is the range of temperature in which an animal uses no additional energy to maintain its body temperature. For a calf less than one month old, that range is between 50°F and 78°F, and any temperatures higher or lower will mean your calf is spending extra energy to keep warm or cool rather than putting that energy towards growth. For a calf over one month old, the TNZ range is 32°F to 78°F. For winter purposes, we’ll be talking about what you can do to keep your calf’s body temperature within the TNZ range.

1. For every degree the temperature drops below the calf’s TNZ, the calf’s energy requirement for maintenance increases one percent. Make sure your calves are getting enough milk or milk replacer along with calf starter to meet these energy requirements. For instance, lets say you have a newborn calf and the temperature is 30°F. You need to make sure that calf is getting at least 20% (50°F-30°F) more energy for maintenance.

2. Give your calf the opportunity to nest. Plentiful bedding is effective in reducing heat loss, and when the bedding is deep the calf can nest to trap warm air around itself. Ability to nest also helps prevent respiratory disease. A lack of bedding means the calf is conducting more of its heat into the cold ground.

3. Keep giving fresh warm water. While no one enjoys the extra hassle of feeding milk and water, water improves feed intake and helps develop the rumen in young calves. Warm water should be provided 2 to 3 times per day.  

4. Any signs of a dirty or wet hair coat should be countered with a solution whether it’s more bedding, allowing more time for a newborn calf to dry before moving it to a hutch, or moving hutches to a drier area. The calf’s hair coat is a layer of insulation and a barrier to the environment, but when covered in dirt, mud, manure, urine, or water, that barrier is ineffective.