Falling temperatures mean calves will have less energy available for growth and immune functions. To maintain targeted performance, they will require additional feed and management.
Dairy calves can grow at an average of 0.8kg per day in their first few weeks under normal conditions if fed sufficient levels of milk – 900g of milk solids, alongside dry feed and water, says Volac’s Jackie Radley.
This is when the environmental temperature ranges between 15degC and 25degC, which is termed the thermoneutral zone.
Ms Bradley says: “During their first three weeks of life and when temperatures plummet to less than 15degC, they will start using energy from feed to keep warm.
“High risk calves – those with a difficult birth and twins – are more vulnerable and will feel cold at higher temperatures. Daily energy requirements increase by up to 30 per cent once the temperature drops below freezing.
“By their fourth week, they will be more robust and will not feel the cold until about 0degC.
“However, high moisture levels and draughts will increase susceptibility to cold stress. Draughts of just 5mph will make calves feel 8-10degC colder.
“Cold stress results in energy being diverted from growth to maintaining body temperature. Consequently, growth rates will fall and the calf will become more susceptible to disease since less energy is available for immune function, meaning calves are more susceptible to respiratory infections and scours.”
Adopting the three-point plan will help calves cope with periods of very cold weather, avoiding stress and maintaining daily liveweight gain.
Cold weather is yet another challenge which you can help your calves overcome if you feed for growth and make sure they are properly housed.
Well-grown heifers will remain on target to join the milking herd at two years of age and are more likely to lead long and healthy lives.
Colostrum management is critical at any time of year, however Volac’s Jackie Radley says she cannot overemphasise the importance of colostrum during winter.
When calves are born on cold days, it takes them longer to stand and suckle. This may mean calves do not receive enough quality colostrum to ensure adequate transfer of immunity.
If you want a healthy heifer, it is absolutely vital it receives three litres or six pints within three hours of birth.
Calves fed colostrum either by stomach tube or bottle within their first few hours, compared with those left to suckle their dam, are almost three times more likely to have adequate immunity to fight off neonatal diseases. Make sure you test the colostrum first with a colostrometer.