I originally wrote the material in this post for the Science on the Farm website. It's re-posted here because I thought it might be an interesting extension for those of you currently studying animal behaviour.
Automatic milking is an exciting technological innovation facing the dairy industry in New Zealand, with the potential to affect farming lifestyles and boost productivity. This technology is quite well-established in Europe, where it's fairly straightforward to train cows to move from an indoors feedlot to a robotic milking system. However, in New Zealand, with its pasture-based farming systems, things are not quite so simple. Tania Blackmore, whose PhD research is examining how best to help cows find their way to the milking robot, comments that "It's not so easy to ensure that individual animals flow smoothly from the paddock to the shed and back to fresh pasture." Automatic milking requires cows to find their own way to the milking shed, without being driven by humans and often on their own, without herd-mates to follow. This means they are faced with learning how to do this, as well as a range of new behaviours distinctly separate from conventional milking.
With existing research indicating that cows can perceive the colour yellow, a Waikato University research project looked at whether cows could learn to approach a yellow stimulus ("sign") as a visual cue to the correct path that they should follow. Firstly, cows learned to distinguish between yellow & grey signs, learning to approach only the yellow stimulus. Why? Because it was associated with a food reward (an example of operant conditioning).
Cows then successfully learned to follow the yellow sign when it was randomly located in simple mazes. Finally, cows used the yellow sign to learn the correct path in a series of more complex mazes, involving multiple turns and the sort of one-way gates that the animals would have to push through on an automated farm. What's more, once they'd learned the visual cue, the cows were able to generalise that learning to a quite different maze layout.
The researchers found that the yellow signs could indeed be used as a visual cue, and that cows could successfully solve mazes when yellow signs were provided - but had difficulty with this task when the signs were removed. The training was successful, showing the potential for cows to learn to follow signs that would make it easier for them to find their way to the milking shed.
Interestingly, while heifers learned faster, older cows remembered what they'd learned for longer. So you can teach old cows new tricks. But this project involved intensive training - up to 30 days for each cow, with 50 tirials a day. This really would be impractical on a working farm. But there are ways to apply this knowledge. Tania suggests that one option would be to put signs on gates that can be opened: once cows have got through them a few times they would learn that it's not possible to push through gates that don't have signs on them.