We have just started to scythe long grass again. The go mad for it. Needs to be started in small portions, but after a few days I just fill the hay rack up with grass (and accompanying weeds) instead of hay and it is finished within 10 minutes.... Milk yield is up as well in the freshly kidded nannies, not so in the runners-through, but don't know if this has got something to do with the grass or not. They still get hay in between, but last year we had no hay left by mid-May, and they were absolutely fine on grass and branches, plus their usual concentrates. Just quite a bit of work... scything every other day.
Scything is done with the strimmer with a metal blade instead of the stringy thingy. Works well.