Infrastructure

Feedpad

Case Study: Low-cost earthen feedpad with solid-roofed shade structure

Background

On-going drought conditions meant Karen and Ian had to re-think their whole approach and in 2007 they changed their operation from an extensive grazing system to a hybrid system. The herd is fed a total mixed ration (TMR) from November to March and then from April to October it is grazed and provided with supplements.

Karen and Ian estimate that they experience up to 100 days/year where heat load affects their cows, so they knew that providing more shade to the herd was a priority. Impressed with what they saw on a trip to the United States, Karen and Ian built two separate, covered earthen feedpads.

Feedpad 1 on the western side located within 300 m of dairy.

Note the central drive alley with portable concrete troughs

on either side.

Feedpad 2 on the eastern side

Two separate compacted clay feedpads share a central drive alley, with portable concrete troughs on each side of the drive alley. The long axis of each rectangular feedpad is orientated north-south. The feedpads each have a raised earthen loafing area located beneath a long shade shed (also running north-south).

The shade sheds, in combination with the feedpads, have meant a substantial reduction in the dips in milk production that resulted from extended hot weather.

Each of the two feedpad shade structures took about three weeks to construct at a cost of about $60,000 (including the earthworks, materials and installation of the shade sheds, troughs and fencing).

• The earthen pads are constructed from on-site clay that was raised and compacted.
• Pads drain to the southern end, then run-off is conveyed into the farm’s irrigation recycle system.

There is a 5-6% slope away from the drive alley and shade sheds to enhance drainage from where the cows stand to eat and to drain stormwater away from the sheds.

Each feedpad is scraped daily to break up the manure pads and enhance drying of the manure. This is part of the property’s mastitis risk management plan.

A land plane is used weekly to scrape manure from the heavily trafficked areas between the feed troughs and the shade sheds. This is deposited on the other side of the shade sheds to form a dry, aerated manure pack that the cows can lie down on.

The feedpads are scraped each year. All the manure is removed and spread directly back on to the property.

The ground slopes away from the drive alley and shade sheds

at about 5-6% to enhance drainage.

Water falling on the shade shed roof flows into gutters, then into

several downpipes and underground piping that is directed to the

recycle system. No stormwater from the roof lands on the

feedpad floors.

Due to the earthen floors, the orientation of the structure is north-south to allow floors to dry out – the sun will strike each part of the floor at some point over the day. The shed has the following dimensions:

• Shade structures – 108 m long x 9 m wide.

Posts are located 9 m apart along the length of the shed; 8 apart across the width of the shed

• Height of roof is 3.8 m on the gutter side; 4.2 m on the high side.
• The roof is single pitch, sloping from east to west at 4.5%.

The shade sheds consist of square tubing support posts that are bolted to concrete footings. H-section steel is used as the trusses, then C-section purlins. Corrugated iron sheets form the roof.

• Rectangular tubing support posts: 125 mm x 75 mm, 5.0 mm wall thickness
• Trusses (steel channel): 150 mm wide
• Purlins: 200 mm
• Footings: 600 mm diameter x 1,200 mm deep; 25 MPa concrete

The central drive alley is constructed from rubble, sourced locally. The central drive alley slopes to the south.

The concrete feed troughs are portable. Their external dimensions are 6 m long, 0.88 m wide, 0.85 m high – back wall, 0.6 m high – front wall.

There are two round 2,700-litre water troughs on each feedpad, at each end of the shade sheds on the side closest to the feed troughs.

Roof design of the shade shed.

What would you change?

Knowing what you know now...

Feed troughs

In future Karen and Ian will remove the concrete feed troughs and construct a concrete drive alley and install a nib wall. This will allow feed to be delivered on the concrete surface and more importantly it will be able to be pushed-up regularly reducing feed wastage.

Karen and Ian estimate that they are losing between 5-10% of feed delivered through spillage from the troughs, so it is well worth the effort.

Location of sheds

Karen and Ian would construct the shade sheds further away from the central alley.

As the sun moves across the sky the shaded area from the sheds moves in the opposite direction. At the western feedpad, the shaded area moves towards the central alley in the afternoon.

If cows want to sit down in the shaded area they have to sit in the heavily manured area between the feed and water troughs.

Ideally, they could sit in a cleaner area of the pad, which could be achieved by increasing the distance between the shade sheds and the feed troughs.

Location of water troughs

We’d also re-locate the water troughs. If they were located on the far side of the feedpads (between the boundary fence and the shade sheds) it might encourage the cows to sit down in the cleaner area of the pad.

Current position of water trough is between the feed troughs and

the shade sheds. This is where a high percentage of manure is

deposited, which often means cows are sitting in fresh manure.

Better position for water troughs – between the boundary fence and

shade shed.