Grains 2 Milk Logo
HomeAbout the programMedia centreSubscribeContact us
Cool Cows and Climate Change - Information for Dairy Farmers
Shade structures
Case Study: Dairy yard shade cloth structure
Case Study: Dairy yard solid-roofed shade structure
Sprinklers and fans
Case Study: Dairy yard sprinkler system

Infrastructure

Dairy yard

Sprinklers and fans


Every dairy yard in Australia should be fitted with sprinklers.

Sprinklers encourage heat loss through evaporative cooling. Sprinkling cows before milking can lower breathing rates and increase milk yields.

If cows are cool when leaving the dairy in the afternoon, they eat more overnight.

While the production benefits are real, most farmers nominate the reduction in flies as one of the best thing about using sprinklers in the yard!

Priorities for cooling cows

1. Use shade first

Minimise heat gain – block solar radiation

2. Use sprinklers and fans

Maximise heat loss – encourage evaporative cooling

Dairy yard sprinklers

Sprinkled concrete loses heat via evaporation and conduction through contact with the cooler water. This reduces its ability to re-radiate heat to the cows standing on its surface.

Sprinklers can be used to wet cows too so they can off-load heat via evaporation. A small amount of heat is also off-loaded via conduction from hoof contact with the cooler concrete surface.

Strengths:

  • Low capital outlay.
  • Can be easily fitted to any dairy yard (or feedpad) with a concrete floor.
  • Effective method of cooling a large number of cows quickly.

Limitations:

  • If droplet size is too small cooling will not be effective.
  • Use in high humidity conditions actually increases heat load on cows.
  • Without adequate air movement, cooling using sprinklers is not effective.
  • Need access to a reliable water supply.

Spray curtains

Spray curtains are another cheap cow cooling option that has the added benefit of keeping flies out of the dairy – appreciated by both cows and people!

Spray curtains can be used in dairy yards but are normally attached to the underside of the dairy shed roof between the yard and the platform.

The example shown was constructed for less than $100 using 19 mm black polyethylene attached to the roof with garden sprinkler sprays inserted into the pipe every metre. It is about 2.5 m above the cows’ feet level.

The sprinklers generate a semi-circle spray pattern that is directed towards the yard side of the shed.


Polyethylene pipe attached to the dairy shed roof for the spray curtain.



Spray curtain water supply and filter.



Spray curtain in operation.


Comments from the experts

The spray curtain is a cheap and effective complement to any dairy yard sprinkler system.

It not only helps keep the dairy shed cool for cows and milkers, it also reduces fly numbers in the dairy – by washing flies off cows on entry and providing a wall of mist that prevents flies from entering the shed.

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 can also be useful in the dairy shed in conjunction with a spray curtain, as in the example shown.

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.

In a dairy yard, 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, between and underneath 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, and not blowing into the dairy.

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.


Fans in a covered dairy yard tilted correctly

to direct airflow downwards to the floor.



A large industrial fan can be used in conjunction with the

spray curtain to keep air circulating in the dairy shed.


Keys to success

Remember that for evaporative cooling to be effective, the cows’ skin needs to be wet – but not so wet that water dribbles down the udder.

Sprinklers

  • AIM FOR a high-volume sprinkler with medium-to-large droplets – avoid a fine mist.
  • COVER THE entire dairy yard, so that all cows are wet in the first 10 minutes.
  • CONSERVE WATER by installing a timer and running sprinklers on an on/off cycle.
  • COW SHOULD not be packed too tightly – sufficient air movement is needed to allow evaporative cooling to work. Poor ventilation results in high humidity and health problems.
  • SPRINKLERS POSITIONED along the sides of a dairy yard need to be mounted high enough to project water up and over cows so it falls from above (ideally 2 m). This will minimise wetting of udders and the risk of mastitis. It will also prevent water being thrown directly into cows’ ears.
  • IF COWS' teats do get wet then either allow time to dry, or dry them with a paper towel before putting cups on.
  • AVOID WETTING cows immediately after milking to prevent teat disinfectant from being replaced with contaminated water while teat orifices are still open.
  • PRE-WET THE dairy yard by hosing, flood washing or sprinkling for the hour before cows arrive for afternoon milking. This helps dissipate the heat stored in the concrete.

Fans

  • ENSURE ADEQUATE number of correctly spaced fans of suitable airflow capacity for the area.
  • ORIENTATE TO work with the prevailing winds.
  • TILT DOWN so they blow air between and underneath cows to enhance whole body cooling.
  • OPERATE ON a temperature threshold to reduce unnecessary power use, and machine ‘wear and tear’.



Australian Government - Department of Agriculture, Fisheries and Forestry