Impact of Cold Stress



What’s happening inside your buildings?

Ventilation and temperature in housed environments are important to keeping youngstock in optimum conditions. On one farm, Smartbell™ found a considerable difference in temperature within a building, reducing growth rates as calves required extra energy for warmth.

Events in the first few months of life have a profound impact on the whole lifespan of animals. To aid the understanding of this, we use a combination of individual animal sensors and environmental sensors. On a farm rearing dairy-bred calves, the animals were housed in an open-sided shed. Hutches were provided for each group and sensors were placed inside.

Fig1: Shed 1 maintains warmth better throughout November, helping to reduce cold stress on calves inside

The range between the warmest and the coldest buildings was 4°C/day. For a newborn calf this takes a lot of energy to overcome, as their ideal temperature is between 15 and 25°C. In lower temperatures, the calf has to expend energy to stay warm (e.g. shivering). For every degree below 15, the additional energy needed is equivalent to 10g of milk replacer at a cost of 2p. Seen above, a group of 50 calves reared in shed 2 has an additional feed cost of £115.25 compared to shed 1 for November. As calves get older, they have a wider thermoneutral zone, but it is still helpful to avoid extreme temperatures.

Calves have other strategies to cope with low temperatures. It is important that they are dry, have sufficient bedding material for nesting and shelter from wind. Increasing environmental temperature without compromising ventilation helps to improve calf health and growth rates while reducing costs. Other strategies could include calf jackets, increasing feed rates or placing older animals in colder zones as they cope better with lower temperatures.