OP, pay attention to The Pasture Talk on this thread. I really do think this is going to drive your tractor buying decision. You need to decide what they heck you are going to do with that pasture.
My land is almost all woods and my JD4700 is just the right size of my use. If I had pasture to deal maintain the tractor might not be the right size.
I don't know much about pastures but I have read a bit for curiosity sake and something a cattle rancher said stuck with me. She said if you are raising cattle you really have to grow good grass for the cattle. She really focused on growing good grass. There is a nearby farm with a herd of cattle. The owners are elderly and I don't know who is taking care of the place but it is in really bad shape. I have watched the pasture quality go from pretty danged good to a weed infested mess over the last decade. In the last year or two the weeds really kicked in and much of the good grass is gone. I drive buy a couple of horse farms and the horses are keeping the grass sort short but the weeds are taking over and you can see what the horses are eating and what they avoid.
If you want to raise cattle and/or horses on the place, it is likely your tractor requirements are going to be different compared to a tractor that is just used to mow that open land.
Later,
Dan