Early dairy sheds had rough floors of earth or stone, often with poor drainage. They lacked a supply of fresh water and a means of heating water, so were difficult to clean. A need for improvement led to the passing of the Dairy Industry Act 1908. However, it was not until about 1920 that hygiene improved due to regular inspections by the Dairy Division of the Department of Agriculture and the building of better-designed walk-through bails and yards.
Cows were milked in stalls or bails, with rear chains to stop them backing out and leg ropes to prevent kicking. The walk-through design allowed cows to exit by going forwards, through a remotely operated back door. The concrete floors had channels to hold milk spills. Water was available for cleaning effluent and a wood-fired copper provided hot water.
Step-up platforms and pit parlours
Variations in shed design made milking easier. A raised cow platform called a step-up made the working height more comfortable for milkers. Handlers could move around the cow to apply the cups from behind rather than from the side, as before.
Pit parlours had trenches about 1 metre deep in the floor behind the cows. When milk-machine operators stood in them they were level with the udder. They would reach up for the clusters of mechanical teats that hung from central milk lines above their head. Cows filed onto a platform from one end and exited at the other.
In the 1950s Waikato farmer and inventor Ron Sharp combined the pit parlour with angled cow positions after seeing angle-parked cars on Hamilton’s main street. He called it the herringbone system, because when viewed from above it resembled a fish skeleton. This design meant that more cows could be milked at once by fewer people, and the cows walk in and out of the parlour by themselves. Within a few years almost all new milking sheds were herringbone design, and in the 2000s the design was still popular in New Zealand and around the world.
Taranaki farmer Merv Hicks invented the rotary milking platform in the late 1960s. His turnstile design consists of a raised circular concrete or steel platform with 16 to 60 stalls. It rotates on wheels driven by electric motors. Cows walk on and are milked, during one rotation, by operators standing outside the circumference of the platform. Cows back themselves off once the cups are removed and make their way back to pasture.
On big rotary platforms, 800–1,000 cows can be milked in two or three hours by two people. Cows on the platform sometimes receive supplementary feed such as grain or palm kernel.
The modern milking process
In the 2000s cows are assembled in a holding yard, which usually has a backing gate to gently nudge them towards the milking area. The cows learn to position themselves for milking, and operators are free to wash teats, attach and remove the cups, and let the cows go afterwards. Milking parlours contain a machinery room with pumps and coolers, and a vat room where milk is stored before it is picked up by tanker and taken to the dairy factory. Yards also have bails where cows can be restrained for health procedures or artificial insemination.
In 2007 building and equipping a milking parlour in New Zealand cost from $500,000 to more than $1,500,000.
Automatic milking machines, which are run by a computer, are used on some farms in European, North American and Middle Eastern countries, where cows are confined and fed indoors. In 2007, Dexcel (now Dairy NZ) in Hamilton trialled the Greenfield project, where cows on pasture voluntarily walked to the milking shed once or twice in 24 hours and waited for their turn on the robot milker – all without human assistance.