Infrastructure

Dairy yard

Case Study: Dairy yard solid-roofed shade structure

Background

This farm in the southern Riverina in NSW has opted for a solid roofed structure over its dairy yard. The 400-cow Holstein-Friesian herd averages more than 10,000 litres/ cow/lactation and with batch calving there are plenty of cows in early lactation in the hot months, so minimising heat stress is a priority.

The farm operates a ‘hybrid’ feeding system. During summer there is no pasture available to graze and the herd is fed a total mixed ration (TMR) on a feedpad, so managing heat stress by using paddock shade is not an option.

The farmer chose to focus cow cooling efforts at the dairy rather than the feedpad because the dairy yard has a cement floor. Increased lameness risk by having cows standing on concrete for long periods was outweighed by the increased risk of mastitis if cows spent all day under a shade shelter in a bare paddock or on a earthen feedpad.

The fact that the herd is milked three times a day further swayed the farmer in favour of investing at the dairy yard.

Initially, sprinklers and a shade cloth were installed, but in 2009 the decision was made to replace the shade cloth with a permanent pitched roof made of steel and corrugated iron that follows the profile of the dairy shed roof.

The shade structure has the following dimensions:

• The dairy yard roof is 30 m by 15 m.
• The roof is 3.7 m high at the eaves – pitched at 20°.
• Open ridge vent is 300 mm wide.

Although it cost more than $30,000, the farmer expects the permanent roof will pay for itself within two summers through sustained feed intakes and milk production, with the added bonus of improved fertility.

Understanding how important air flow is to maximise evaporative cooling with sprinklers, and having observed that many hot days in the district also tended to be very still, the farmer has also installed 3 large fans at the entry to the shed direct air over the holding yard.

On hot days, cows spend most of their time between feeds in the dairy yard (cows can also access the dairy shed, which provides the same area of shade).

What would you change?

Knowing what you know now...

Six more fans will soon be installed further down the length of the dairy yard to help keep air moving over all cows in the yard.

The sprinkler system will also be refined with a timer, providing an adjustable on/off cycle that will conserve water.

The next major cooling investment on this farm is likely to be a shade structure over the feedpad, done in conjunction with other developments at the feedpad that will reduce mastitis risk.