Stuart and Julie Young, and their adult sons Alec and Jack, farm at Wyuna East in northern Victoria. They milk 400 mostly cross-bred cows, producing 7500 to 8000 litres per cow per year.
After seeing the impact of a record-breaking heat wave in the summer of 2012-13 on their cows, the Young family knew they needed to do more to manage heat stress.
After considering a few alternatives, the Youngs opted for a shade-sail structure installed over their dairy holding yard. Comprising four large sails, joined together and suspended by nine steel posts, the structure covers a total area of 521 square metres.
"Since the shade structure was installed, our cows have fallen by only one to two litres per day during really hot periods, and they have then fully recovered," Stuart said.
At a total cost of $22,000 plus GST installed in 2014, the Youngs' shade cloth structure worked out at $42 per square metre. The Youngs are in no doubt that the structure paid for itself within just two years.
A shade sail structure must be well engineered and built to withstand not only its own weight but also the substantial loads from strong winds, heavy rain and hailstones. Designing and installing a substantial shade sail structure will require professional assistance.
The function of the Youngs' shade cloth structure has been aided by the east-west orientation of dairy holding yard. Where the holding yard is oriented north-south, the preferred approach is to extend the sails an extra metre or two beyond the western perimeter of the yard, and plant shrubs and small trees outside the western perimeter to ensure cows are in shade when the sun drops low in the sky in the late afternoon.
In the hot months, the Youngs opt to dry off most of the farm and feedlot their cows in paddocks near the dairy. After milking cows are given unlimited access to the holding yard, which enables them to cool down between feeding.
The Youngs are now gradually shifting from their split-calving system towards autumn calving. This will mean that in January, February and March they will have fewer milking cows to keep cool.
The Youngs plan to do more in the next few years to be better able to cope with hotter, drier conditions in their region, which often now extend from October through to March. Planned actions include planting more tree belts, installing sprinklers at the back of the dairy holding yard and adding a timing system to the sprinklers.D
For information on shade-cloth and solid-roofed structures and design considerations, go to website http://www.coolcows.com.au/Infrastructure/introduction.htm.
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