Protecting your calves from cold stress for growth and health

22 February 2021

All animals have a thermoneutral zone, which is the temperature range where they do not have to use energy to maintain their body temperature.

For calves, this is generally between 15 ˚C and 25˚C. This range is important to know because young calves are much more susceptible to the effects of cold temperatures than adult cattle.

In addition, older calves may have a layer of fat and thicker skin, unlike calves under 3 weeks old which don’t and are much more susceptible to cold weather effects. When temperatures drop below 15˚C, the calf uses energy to generate heat to keep warm, which results in lower growth rates and increased susceptibility to disease.

Some of the main factors that affect how susceptible a calf is to the cold are: -

  1. Genetics. For example, Jersey calves have less fat and will feel the effects of cold more than a Charolais calf.
  2. Nutrition. 3 litres of colostrum within the first 2 hours after birth will provide vital energy and help to build up calf’s immune system.
  3. Environment. Clean, dry bedding is essential for calves to regulate their body temperature. Damp bedding simply ‘sucks’ energy from the calf while it is trying to keep warm.
  4. Air speed. Air speed of more than 1m/s (2.2mph) will make calves feel cold. Draughts create a downward wind chill on calves and compound cold stress.
  5. Health. As the immune system uses a lot of energy, healthy calves will regulate their body temperature better than sick calves.
  6. Difficult calving. A hard or stressful calving will make the calf feel the cold sooner.

It’s crucial to have a plan in place for when the weather gets cold, particularly when temperatures drop below 15˚C. An important consideration is that damp and windy weather will dramatically increase the calf’s susceptibility to cold, for example, a 2.2m/s (5mph) draught will make calves feel like the temperature is colder by 8°C to 10°C.

When the temperature falls, there are a number of actions you can take to help maintain the calf’s temperature, supporting growth and helping to promote calf health.

  • Calf jackets. Good quality calf jackets are useful for keeping calves warm. They should be waterproof but breathable, have sturdy adjustable straps and be machine washed between calves.
  • Dry bedding. Ensuring calves can nestle in a clean and dry bed is essential to help them regulate their body temperature. Good floor drainage reduces the moisture and is important because damp bedding will extract energy from the calf as it tries to keep warm.
  • Increase feed rates during cold periods. The rule of thumb for a calf younger than 3 weeks old is to feed an extra 100g of milk powder or 1 litre of whole milk per day for each 10˚C drop in temperature below 15˚C. Increasing the amount of starter fed also helps generate heat.
  • Housing. Providing shelter for calves to lie under, such as canopies, form effective barriers to avoid draughts at calf level.
  • A heat source. Providing a heat source such as an infra-red lamp really helps newborn calves avoid a chill when waiting to be fed.

These simple management tips can have a large impact on driving growth and improving health in one of the most important periods of life.

 

by Katie Tiernan, Calf Specialist