Bit curious on this. A lot of difference in area, but with as wet as it was down your way early do you not think that is why your alfalfa not yielding? Up here grass can take any amount of water and produce like it appears in your waterways comment(assuming you can get it off), but alfalfa almost seems to stunt when too wet. Given the cost to terminate/reestablish alfalfa my tendency would be to leave it - unless there were actual deadspot areas due to winterkill, too many ruts, moles, etc.
Cold and wet was my concern and thought on the first cutting, its been less wet and significantly warmer/hotter for second cutting. We will see ow the third does in 10 days or so and fourth later than that but it being about half production now has me thinking that it will get terminated.
I understand the thoughts on trying it one more round but this is ground that is fully capable of cranking 250 bpa+ corn and 70 bpa+ soybeans, I can't afford to have it sub produce alfalfa. I usually rotate out of alfalfa in 4-5 years anyway.