Now that winter is here, it’s time to think about how to improve your calf management to minimize cold weather stress. What feels “cold” to a newborn calf may not feel “cold” to a person. A calf is most comfortable when the amount of body heat produced is about equal to the amount of body heat lost. This is called the thermoneutral zone. It ranges from about 50 -78°, assuming the environment is dry and draft-free. Once the temperature drops below 50°, or the calf is wet, she has to burn extra energy to keep warm.
Calf Comfort:
The goal of caring for calves in cold weather should be to keep them warm and dry and to feed enough energy and nutrients to allow for body weight gain. This can certainly be a challenge, due to the fact that calves lose body heat in 4 ways:
Evaporation:
This happens when the calf is wet and she uses her body heat to dry the skin and hair coat. The simple solution here is to dry calves with a bath towel at birth. Create enough fluff in the coat to provide a layer of “insulation”.
Radiation:
Heat flows from warm objects to cold objects through the air. The warm object is the calf, and the cold one could be the ground or snow. To reduce heat loss, provide a barrier, such as a blanket, that will reduce heat loss from the calf.
Conduction:
Heat is transferred from one solid object to another. This happens when the calf comes in contact with a cold surface, such as wet bedding. To prevent heat loss through conduction, make sure the calf has plenty of clean, dry bedding.
Convection:
Wind or a drafty environment will create heat loss when air passes over the calf’s body. This can be minimized by providing natural or man-made windbreaks, or simply providing a calf coat.
An obvious way to reduce heat loss from a calf is to provide a calf coat. These coats are available from a number of different suppliers, including Genex and Select Sires. A study in North Dakota showed an increase in average daily gain when calves were provided with coats; (1.2 lbs/day without coats, and 1.4 lbs/day with coats). Here are a few tips to use calf coats effectively:
1. Give priority to smaller and younger calves. Smaller calves have greater potential to lose body heat, because the ratio of surface area to body mass is much greater than for a larger calf.
2. Make sure calves are dry before putting on calf coat. Putting a coat on a wet calf will only trap moisture and not allow the calf to dry.
3. Make sure the calf coat is dry before putting it on the calf. Ideally, coats should be washed and dried in between calves.
4. Use enough bedding to insulate the calves from the ground. The bedding must be dry and clean. This point cannot be stressed enough!!!
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