The requirement for additional energy management in a calf house varies according to the calf/calves, the weather, and the quality of the calf house environment. In the first week of life a calf is likely to spend extra energy to keep ‘warm’ below an air temperature of maybe 10oC. The actual lower critical temperature for any one calf will depend on all those aspects that will influence the energy dynamics of the system:
Calf Jacket benefits
Genetics – Jersey calf will feel ‘cold’ before e.g. Charolais calf
Birth conditions – normal/prolonged; premature/low birth weight; single/twin
Health – vigour/health vs apathetic/low feed intake
Nutrition – quality and quantity and timing of colostrum; energy density and dilution of milk powder, adequate intake
Air speed – less than 1m/s is good; a draft is negative
Dry bedding – essential; damp bedding extracts energy from the calf
Calf Jacket protocol
Jackets must be made of breathable materials…
1. Locate max/min thermometer in calf house
2. Reset thermometer every morning during autumn/winter housing
3. Decide on set temperature for your system, eg 10oC
4. Agree starting protocol with staff :
eg. 3 consecutive night-time minimum temperatures below e.g.10oC
5. Calves must be dried off before using jacket
6. Place clean jacket on every calf below one week of age and on entry to calf house or a soon as dry after birth.
Entirely dependent on the energy dynamics listed above; what is the condition and appetite of each calf? What are the expected weather conditions? OR keep on calf until 4 weeks old. Can be left on longer if needed with no ill effects as long as it fits comfortably.
1. Know the weather forecast; steady or rising temperatures OK, falling temperatures, beware removing jacket too early
2. Agree with staff a temperature protocol for healthy calves e.g. one week old >10oC OK; two week >5oC OK; more than 3 week >2oC OK
3. Refer to recent night-time minimum temperatures
4. Consider individual calf condition; feed intake, health, growth rate
5. Remove jacket in morning not afternoon
6. Breathable jackets can be left on even with daytime temperatures unto 19 – 20⁰C if night time temperatures fall below 10⁰C
7. Remove excess dirt from jacket with hose/light powerwash or pre-soak
8. Wash jacket @ 40-50oC with detergent and dry.
9. Line dry or dry overnight in aired room. Do Not Tumble Dry.