Infrastructure

Feedpad

Sprinklers and fans

Permanent structures over feedpads (or freestalls) provide shade which minimises cows’ heat gain. Incorporating infrastructure such as fans and sprinklers assists heat loss through evaporative cooling.

The combination of shade, sprinklers and fans means farmers have much more control over environmental conditions.

These structures require significant investment and professional advice is critical to success.

Feedpad/freestall sprinklers and fans

Strengths

• Fans are very effective at cooling cows when used in conjunction with sprinkling – their combined effect is greater than the impact of each alone.
• Provide effective air movement and cooling in confined spaces such as covered dairy yards, sheds and freestalls.

Limitations

• Require a concrete floor to manage effluent run-off.
• Fans require close access to sufficient power – a limiting factor in many rural areas of Australia.
• Fans are expensive to buy and run.

For fans to cool cows effectively:

• the ambient temperature must be lower than the cow’s body temperature
• the cow’s skin must be wet (through sprinkling or sweating).

Fans

Increasing airflow from 0 m/sec to 1 m/sec increases heat loss from a wet cow three-fold.

Fans can, therefore, be a useful complement to sprinklers, especially on warm to hot days when there is little or no wind.

Fans only help cool cows when:

• the air temperature is lower than the cow’s body temperature (39°C)
• the surface of the cow is wet.

Fans should be mounted above sprinklers so they remain dry and tilted 20-30° down from vertical so that they blow down to the floor, over and around cows. If fans are aimed too high, their effectiveness will be reduced.

They are usually placed in a row with their back to the prevailing wind.

Fans range in cost from about $550 to $2,000 each, depending on their design and capacity.

Check the efficiency rating of the fans and buy the most efficient. Only use fans with sealed motors.

This is a ‘Shade Tracker’ evaporative cooling system in use on a farm

in the US. This computerised system adjusts  the amount of water

output according to the temperature and relative humidity, and follows

the shadow of the shade shelter through the day.

This ensures that the cool air is always blowing into the shade.

This US farm is using ‘Korral Kool’ evaporative coolers. These are a

fixed cooling system used in conjunction with automatic blinds fitted

to each side of the shade shelter to shade the cows in the mornings

and afternoon when the angle of incidence of the sun is at its

greatest. This photograph shows the blinds in the half way position.

Keys to success MANAGEMENT IS easier if the feedpad/freestall structure is located close to the dairy, as staff can monitor the herd while preparing for milking or post milking clean-up. CONSIDER THE effects of prevailing winds, radiation from the sun and rainfall. Structures need to be able to withstand extreme weather conditions. USE AN engineer with experience in designing these systems.