Training cows to milk themselves
The Greenfield Project at DairyNZ has been set up to investigate whether a fully automated milking system can be used on New Zealand's dairy farms. The aim is to reduce the amount of labour needed to run a farm by getting the cows to move themselves around the farm and by using a robot to milk the cows.
The cows on the Greenfield farm have to be taught how to use the milking robot (called Merlin) and how to take themselves to be milked. This is done by offering rewards (called “operant conditioning”) and getting them used to it slowly (called “habituation”).
More information about the farm layout and how it works can be found in the Robotic milking focus story.
Teaching the cows to use Merlin
The robotic milking relies on cows learning how to use the robot (Merlin) to get themselves milked.
First, a cow is walked through the machine with both of the gates open. Then she is held in the machine for 4-5 minutes without being milked. After doing this 2-3 times the farmer helps the cow to be milked by Merlin by pushing her gently into place for the robot to attach the milking cups. Crushed barley is given to the cows as a reward each time they are in the machine. (This is like giving them lollies for being good).
Teaching the cows to take themselves to be milked
A milking system that is fully automated requires the cows to get themselves to the dairy for milking (the farmer does not need to go out and fetch them). Once the cows can do this, they can go and get milked at any time, day or night. The aim is to get a steady stream of cows through the dairy so that the milking robot (Merlin) is always in use.
On their first day on the farm, the cows are walked around the property. They do a loop from the paddock, through a slightly open gate to a water trough, along the race to Merlin, and back to a new paddock. One-way gates stop the cows going backwards along this loop. The cows are taught to use the gates by leaving them ajar for a few days and giving them access to water, grass or barley once they go through.
When the Greenfield farm was first set up, the cows learned that they got rewards for going through the gates and ended up visiting the dairy shed too often. As a result, selection gates were installed. These control whether the cow is sent to the dairy or back to the paddock.
Another problem at the start of the project was that some of the cows learned to open the one-way gates in the wrong direction. This could have happened when a cow reached over the gate to get to some grass, accidentally pulling the gate open. The “reward” – perhaps access to fresh pasture – would have re-inforced the behaviour. The next time she was in the selection unit, the cow would have nudged her head against the gate again, and eventually caused the gate to open.
Again, access to fresh pasture on the other side would cause her to keep repeating this behaviour, and improving her ‘gate opening technique’.
As a result, the gates were modified to stop this happening.
The scientists think that cows learn to walk through the selection units to the dairy much faster if there is an experienced cow for them to follow. The team at the Greenfield project are investigating whether cows already on the farm can teach new cows to use the system without any help from the farm staff.
