While researching  Large  Milking Operations.
(For another project)
Came across this statement, at the end of, 'how things work', to milk with robots.
(Had my good laugh, for the day)

“ …cows that try and sneak back in to be milked early will be rejected.
Cows that refuse to move out of the system when they are done
receive a small electrical shock to prod them on their way.  …”

Could be some valuable insight, taken from those methods.
Which,  could be applied to other areas.

Another statement, about how it works:
“ …a bucket with a pre-measured amount of sweet pellet treats,
pops out in front of her so she can eat while being milked. …”

So in a nut shell.  
The cows, that, NEED, to be milked, are milked.
And those that just  WANT the, ‘… pellet treats…”
Don’t get any !