Infrastructure

Paddocks and laneways

Case Study: Paddock sprinkler

Farmer’s name: Terry

Facts about the sprinkler system:

Designed by: Local ex-farmer
Installed by: Terry
Lifespan: Been operating for seven years without failure, minimal rusting

Other cooling infrastructure on this farm:

Loafing paddock 100 m from dairy with tree shade, water and hay rings

Background

Terry farms in an irrigation district. He bought a towable ‘Cow Cooler’ water jet sprinkler with a geared head after hearing about its success from a number of other farmers.

The unit is mounted on a frame that is equipped with a fire fighter pump and long suction hose that can draw water from on-farm channels, dams or tanks. The system was designed by an ex-dairy farmer from Kyabram in Victoria.

The system is suited to most dairying regions that have dry temperate climates with low humidity, as long as water is available for pumping. It requires a close, reliable water source.

On days where the temp is 30°C or more, the ‘cow cooler’ starts operating at 10-11 am. The cows can move in and out of the water jet while they are grazing or feeding from the hay rings if they are confined from fresh pasture.

Terry said the cows will come and cool down then move back to grazing away from the water jet. When they are cooling themselves they never stand directly under the jet of water but rather stand close to the mist that comes off the jet in the ‘evaporative zone’.

On very hot and humid days over 35°C the cows are shifted from the pasture paddocks to a loafing paddock with tree shade, water and hay rings located within 100 m of the dairy. During these days the cows move back and forth from the shade to the water jet, and some also feed from the hay rings.

The unit runs on petrol and the petrol tank holds about 10 litres of fuel, which can operate the pump for about 18 hours at 75-85% of maximum engine revs.

The herd facing downwind cooling their backs.

Terry’s comment

The pump can be used for other applications by simply removing the water jet (the green unit shown in the photographs).

I use it for general washing and flushing jobs around the farm.

On average, petrol is added every second day at a cost of about $12.50 (e.g. 10 L of fuel at $1.25/L).

The unit was bought in 2002/03 for $3,300 ($4000 at today’s prices) and includes the following features:

5 HP motor with 5 cm Davey fire fighter pump
30 m; 5 cm suction hose
3.5 cm jet (orifice diameter)
Geared head to control movement of the jet – it can be stationary or complete a full rotation
Small splash plate creates a mist of water that cover the cows
Application radius is 30 m
Height of sprinkler orifice – about 2 m from the ground
The head is angled at about 20° and shoots water to a height of about 5 m
Water use efficiency is between 3,000 and 3,500 L/hr.

Terry’s management tip

Shift the cow cooler daily, otherwise cows will pug the wetted area then start sitting in the wet, muddy patches.

If this occurs then the cell count may increase dramatically so get onto it early.

Set up into the wind – cows standing downwind in

the ‘evaporative zone’, not directly under the water jet.

Geared head which can stay stationary, complete short arcs or 360° rotations.

Comments from the experts

The cow cooler adheres to the key principles of a sprinkling system by providing large droplets of water that wet the cow’s hair coat to the skin. The water then evaporates.

Portable and quick to set up, it is a good way to help cool large numbers of cows in the paddock when shade is limited. It is a cheap investment that can also be used for other jobs around the farm.

It is an option suitable for those farmers who graze cows throughout the hot season. It should be considered as a supplement to paddock shade, not a substitute.