Managing in the heat

Cool season preparation

Check evaporative cooling: are you doing all you can?

Having investigated options to increase shade, the next thing to consider is evaporative cooling. Evaporative cooling involve the use of sprinklers, fans or a combination on cows on yards or feed pads with or without a shade shelter to increase air flow and overcome the limitations of cows trying to cool themselves by evaporation (sweating).

It is important to understand the difference between the main types of evaporative cooling systems:

System	How it works	Comment
Fan and pad	Works by spraying very fine water droplets into the air, cooling the air as the droplets evaporate.	Used in many greenhouses Suitable for housed dairy systems Very efficient, but expensive
Fog	Works by spraying very fine water droplets into the air, cooling the air as the droplets evaporate.	Very efficient, but expensive. May exacerbate humidity problems.
Mist	Works like the fog system, but uses a larger droplet size that drops slowly to the floor, evaporating as it falls, rather than staying suspended in the air.	Effective, but difficult to use in windy conditions or with fans. Can cause cow health problems if used in enclosed areas.
Sprinkling	Works by wetting the cow's hair coat to the skin. The water then evaporates and cools the cow's hair and skin.	A moderate to large size water droplet is essential

Cows off-load most of their heat through evaporation from sweat and breathing. Anything you can do to assist their evaporative cooling processes is worthwhile.

To be effective, sprinklers must wet the cows' hair coats to the skin. Good air movement is also essential.

Evaporative cooling can be provided in 3 locations on a dairy farm: