It is common to see all types of animals in the heat without protection from the sun. While farm animals have various ways of coping with heat, a very important one is to seek shelter or shade. Shade helps reduce heat loading from the sun, especially for dark-coloured animals that readily absorb heat. In the absence of adequate shade, animals will try to find any scrap of shade they can — it could be from a fencepost or another animal’s shadow.
For sheep, long wool is a good insulator, protecting them from cold. In warmer temperatures, longer wool protects sheep only for a short time as the long wool traps heat against the body and prevents radiation. Closely shorn sheep are able to sweat more effectively but sweating only works in the initial hours of being exposed to high temperatures. Shorn sheep kept in yards or paddocks without shade have no protection from the sun and may become sunburnt and heat stressed. Panting is the main way sheep deal with heat stress but this also has little cooling effect at ongoing high temperatures.
Cattle lose their body heat by evaporation of sweat and by panting. Cooler temperatures under trees promote heat loss. Shade is as important in cooling as it is in providing protection from the sun.
Some cattle breeds are genetically more heat tolerant than others. However, heat tolerance is also behavioural. Cattle may deal with lack of shade by grazing and walking in the cool of the day or at night, and by standing still where there is good airflow to help evaporation.
The RSPCA believes that all animals should be provided, at the very minimum, with appropriate shelter, food and water. Shelter particularly refers to protection from climatic extremes. Animals have various mechanisms for coping with heat but the most obvious one is seeking shade.
In the absence of shade from trees, farmers need to provide livestock with other forms of shade for their physical comfort. Alternative shade can come from tarpaulins, shade cloth or sheds. Alternative shade structures must have good airflow or the heat will become intolerable and animals will be forced to leave the shade.
To replace the water lost in cooling their bodies, animals need plenty of cool, clean drinking water. When water becomes warm, animals drink less. Therefore, during periods of heat, it is important to check regularly and provide animals with fresh, cool water.
