I do not feel it would (be safe) work.
The 2.5 in tubing will hold the force of moving forward and braking; the problem will be from side force in turns. A piece of tubing that long will not withstand that kind of forces because they are multiplied for every inch in length.
This leaves the chains to hold the load and there is no way a 1000 lb rated tie down point is going to hold a gooseneck full of cows.
If you need something that would work on say 10 differant pickups without installing a gooseneck hitch in each pickup I would be thinking converter dolly. A small trailer that would hook into your trucks reciever and has a gooseneck ball just above the axle.