Calf Jacket & Heater Protocols

Understanding calf temperature

In the first week of life a calf is likely to spend extra energy trying to keep warm below an air temperature of 10oC. The actual lower critical temperature for a calf will depend on any factor that influences the energy dynamics of its system. The  requirement for additional energy management in a calf house varies according to the individual calf, the weather, the quality of the calf house environment and the items detailed below:

Some breeds, such as Jersey’s will feel cold before other breed such as the Charolais. Ask us for details.

Birth Condition
Note calf birth conditions and adjust your approach for low birth weight, twins & prolonged pregnancies.

Naturally calves with good vigour & health require less heating vs apathetic, poorly feeding calves.

Quality, quantity and timing of Colostrum is key, along with energy density and milk power dilution.

Air Speed
Less than 1m/s is ideal as anything over this can create drafts which lower the calf’s temperature.

Dry bedding is essential. Damp bedding will rapidly extract energy from calves, lower core temperatures.

Calf Jacket Protocol


  • Reset thermometer in calf house every morning
  • Decide on set temperature, e.g. 10oC
  • Agree starting protocol with staff, e.g. 3
  • consecutive night-time Min temps below 10oC
  • Ensure calves are dried off before using jacket
  • Place clean jacket on every calf below one week of
  • age and on entry to the calf house


  • Know the forecast, i.e. rising/falling temps
  • Agree finishing protocol with staff, e.g. one week
  • old >10oC = OK. Two week >5oC = OK.
  • Refer to recent night-time minimum temps
  • Consider individual calf condition
  • Remove jacket in morning, not afternoon
  • Remove dirt and wash jacket @ 40-50oC

Setup and Management

  • Provide waterproof ring main and sockets (IP66 standard) above pens
  • Provide a frost stat on the circuit; ensure power rating can accommodate all heaters
  • Use 250W infra red bulbs over pens (1 x 2 pens)
  • Use 1,500W linear heater (IP55 standard) wall mounted or hanging above group pens
  • Hang linear heater at the height recommended by the manufacturer
  • Agree set temp for frost; override for sick calves

Related SEV Branch