HEALTH WINTER CARE
Keep calves clean and cosy as temperatures drop Westpoint Farm Vets offers a few timely tips and pointers on keeping calves warm this winter. TEXT TIM POTTER
Cosy calves: there should be plenty of straw to create a ‘nest’
Taking steps to protect calves from the cold, and ensuring they are warm and dry, will reduce the risk of disease and help to maintain growth rates. Ventilation is vital for removing stale and humid air – as well as any viruses and bacteria that could be lurking within it. So, even in cold weather, a good supply of fresh air is essential. But producers should check that the airflow is above calf level, as animals kept in draughts will not perform. Cold, chilled calves will divert energy from growth into simply maintaining their body temperature. Close gaps under doors and gates that create draughts at the level where calves are lying. And, if calves are housed in large or exposed airspaces, consider making lower covered areas where they can keep warm. As temperatures drop, calves will begin to burn extra energy to maintain their body temperature. So it’s vital that producers take steps to avoid a fall in growth rates. The lower critical temperature (LCT) is the temperature below which an animal requires additional energy to keep warm. In the first
three weeks of life the LCT is between 10 and 15oC and as the calf grows its ability to cope with the cold improves and the LCT drops. Calves older than three weeks have a lower critical temperature of around 6oC.
Immune function
During the winter months it is possible to maintain growth rates by increasing the amount of feed the calves are fed (either by increasing the volume or, for those animals on milk replacer, increasing the energy concentration). The cost associated with this is easily recouped through maintaining growth rates, as well as reduced disease incidence. A well-fed calf has better immune function. Plenty of clean bedding, to reduce calf contact with soiled straw, is also important. Calves like to ‘nest’ so they must have sufficient straw to keep warm and reduce stress. The nesting score is a way to quickly assess whether bedding is deep enough (see Table 1). The aim during winter should be a nesting score of 3, meaning that there is plenty of straw for the calf to nest and trap
a layer of insulating air around itself. Calf jackets are a useful tool and provide protection from the cold. Consider using jackets for calves younger than three weeks old when temperatures fall below 15oC. Make sure calves are dry before fitting jackets and always thoroughly wash and dry jackets between calves to avoid disease transmission. When taking jackets off, always do in the morning when the environmental temperature is at its highest, because this allows the calf to adjust before temperatures begins to fall overnight. Table 1: Nesting scores for calves bedded on straw ● Nesting score 1
Legs entirely visible when the calf is lying down ● Nesting score 2 Legs partially visible when the calf is lying down ● Nesting score 3 Legs not visible when the calf is lying down
cowmanagement JANUARY/FEBRUARY 2021
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