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Maintaining calf performance in colder weather

As temperatures start to drop, now is the time to put plans in place to ensure that calf growth rates don’t drop off too.

In cold weather, calves will divert energy reserves to maintaining a comfortable body temperature rather than into growing, and are also more susceptible to illness and bacterial infection. When prolonged cold spells come, extra feed must be supplied to help compensate for this additional energy requirement.

Cold Stress

Just as heat stress is an issue in the summer for livestock, cold stress will become an issue for most calves when temperatures reach below 10 °C, or Lower Critical Temperature (LCT). 

The diagram shows the Thermo-Neutral Zone (TNZ) temperature range, within which an animal over three weeks old uses no additional energy to maintain its body temperature, plus the LCT and UCT (Upper Critical Temperature) where extra energy is used to keep warm and cool respectively.

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The LCT for a calf, however, will depend very much on its age. Remember that calves that are less than three weeks of age have an LCT of just 20°C.

Newborn calves are particularly susceptible and, after just 18 hours exposed to low temperatures, will exhaust all of their energy reserves trying to stay warm. 

In prolonged colder weather, a calf can quickly move from a situation where they are making daily live weight gains into one where they are in negative energy balance.

If this happens, a calf is using more energy to keep warm and survive than the amount of energy they are consuming. Calf jackets are a good investment to help calves retain as much heat as possible, especially in the first few weeks of life. 

As winter rolls in, keep an eye on the forecast so you can see if colder weather is approaching. Consider getting a simple humidity and temperature monitor to keep track of the conditions in the calf house, as sometimes sharp drops in night-time temperature can affect calf performance without you knowing.

Use extra feed to combat cold stress

Providing extra energy and protein by increasing amount of milk replacer being fed is the best way to maintain strong calf performance during cold weather. These changes need to be made gradually to avoid stomach upset and bloating which is why it is good to know when a cold spell is coming.

Don’t skimp on feeding heifers with supplementary concentrates, minerals and vitamins during the cold weather either. Depending on a heifer’s age, not supplying enough energy and the right nutrients during the winter period this could have serious implications on productivity and health of future performance and calves.

Mixing CMR

How much extra CMR is required?

The rule of thumb is that for every 1°C below the Lower Critical Temperature, add an extra 11g of CMR. Try to increase the CMR feeding rate by changing the concentration, i.e. 15% to 17%, rather than increasing litres fed per day.

Cold weather mix rates

Beware of Pneumonia

While warmer winters mean that cold stress is less of an issue, a mild and wet winter brings with it the risk of increased calf pneumonia, the second biggest cause of calf loss in the dairy industry worldwide. Pneumonia can strike early while the calf immune system is still developing, and the early signs are hard to spot so prevention is always better than cure.

  • Ensure adequate intakes of high-quality colostrum in the first 24 hours
  • Maintain high levels of pen hygiene
  • Ensure housing is well ventilated (but not draughty at calf height)
  • Remember that lower stocking densities can reduce infection pressure
Top tips on calves in the cold weather

For more information on caring for your calves this winter, please contact your ForFarmers Account Manager or contact us here