Robotic Milking in Waikato

John and Margaret Fisher were early adopters of robotic milking machines, adapted to the typical New Zealand pasture-based production system. They started with four De Laval robots in an automated milking system (AMS) in March 2011 and have now used them for five years with minimal breakages and disruptions.

The Fishers watched the DairyNZ (Dexcel) Greenfield Project begin in 2001 with the aim of bringing international voluntary milking machines into the NZ pastoral dairy farm setting, whereby cows would have to walk themselves to the milking parlour and be returned to new pastures. Initially sceptical, John was convinced that AMS would work in the NZ context when the Greenfield Project introduced three-way grazing (new grass every 8 hours).

When the opportunity to re-fence the farm came along, the Fishers made the considerable investment to buy four robots and modify the yards, machinery, raceways and fences. The labour cost savings at milking times were only marginally economic when weighed against the additional capital, but there have been further benefits in longer cow life, lower replacement rates, good reproduction rates (empties 4-6% and 6-week in-calf rate 75-80%) and lower animal health costs. The number of full-time staff members has gone down by one. John and a fulltime farm manager comprise the work force.

They currently milk 240 cows on a 80ha flat farm, part way through a transition to 300 cows 50/50 spring and autumn calving, targeting 150,000kg milk solids annually. The planned 3.75cows/ha stocking rate with some supplementary feeding would result in 500kg/cow and 1875kg/ha.

This season has been good for pasture growth and John has been able to reduce the purchased feed, being a mixture of palm kernel, dried distillers grain and wheat bran pellet, fed in the robot area to attract cows. Home-grown maize silage and grass silage are also fed out. Every cow can access the supplementary feed she requires and they can take their time after milking, without being pushed around by more dominant cows.

Cows get up to 1kg/day of in-shed feed post-calving to ensure adequate intakes of magnesium and calcium and then drop back to half that intake later in the season. They are fed as they milk and out of feeding troughs as they exit the machine area.

All the feed area has now been roofed to provide shade and keep the rainwater out of the effluent system.

Response to the very low milk price included less supplementary feeding and more pasture grown and harvested, because of the favourable season. The move to split calving is because of drier summers generally, the opportunity to carry over cows that do not get pregnant with their seasonal companions, better use of robots for winter milking, and smoother operations during the spring peak, when cows had to learn the voluntary milking system and were at peak milk volumes.

John has signed a winter milk contract with Fonterra.

Cows have to be trained to act individually, making their own decisions to seek milking, the in-dairy feeding and the new pasture. As herd animals, this means a change in behaviour, but John said it is amazing how quickly they pick it up. They may have to walk one kilometre from the pasture to the parlour, sometimes even meeting cows returning the other way.

The new fences were placed so that every cow passes through a “smart gate” as they change paddocks. If a cow returns prematurely the gate refuses her access to the milking machines and the supplementary feed. The gate works on a transponder around the cows’ necks.

Cows are milked from 1.5 to 2.8 times per day, with the average 1.8. Milking machines are available 24 hours a day and the fewest cows come through between 2am and 5am so cows can be lined up waiting at more popular times of the day.

The recommended ratio of cows to milking machines is 90 to one, but that is for a cow barn system where cows only walk 100 metres. The opening of the smart gate for each cow can be varied, so milking frequency can be cut down to 1 or 1.5 times a day for a cow that is not cycling or in poor condition. The whole herd could be slowed down in a drought situation, when pasture is limited.

“Cows learn when it is time to change paddocks and if they get rejected from the milking area they quickly move on to another paddock,” says John.

Voluntary milking stations send alerts to John and his manager when something goes wrong and a machine shuts down. It could be cows treading on cups on the ground or if several cows in a row produce low milk yields. The machines monitor the yield out of every quarter at every milking. If a cow doesn’t give 80% of the previous milking the machine will try three times to milk her out and then put her back in the yard. If that happens three times in a row the alert is sounded and the robot shuts down. If that happens at night the other three machines will cope, but if it happens in the day it must be rectified quickly, because at peak season the loss of one machine for one hour can take the rest of the day to catch up in cow flow. John said alerts requiring intervention occur on average once a day. But they do receive several alerts of low yields, usually because the robot hasn’t picked up all four teats. In that case the cow is automatically detained and sent round for a second milking, without human intervention.

John says “I still think the economics of going to voluntary milking by robots are marginal, but it is a lot easier on us, and we have achieved higher production per cow and greater management efficiencies.”

Most AMS farms in NZ have a high-input feed basis, which makes the economics challenging when the milk payout is low.