According to Wikipedia a 250 pound pig will typically have a dressed weight of 180 pounds and a retail cut weight of 144 pounds. (The number of 144 pounds is fairly close to your 132.01 pound dressed out pig.) This is a net of 72% dressed weight, with only 57% of the original live weight becoming retail cuts. Another method to convert from live weight to dressed weight is to multiply by 0.67. You'll have to do the math, because my calculator is broken.