I would ask your local dairy farmers - many of them will have a Jersey or two in the herd, and they're worth practically nothing 'in the fat' when they are no longer able to perform in the herd.

Our local Jersey farmers (now retired) used to let the old gals expire on the farm.

And some sell off the old dears to be used to rear orphan calves in suckler herds - so a local suckler herd may have an old Jersey now too old for even that job that they'd let you have.
Alternatively, you could pick up a Jersey bull calf for next to nothing, and let your girl mother it... then in about 18 months, pop it in the freezer and get another.

Good luck!