While there may be some frozen semen used in "specialty" type hog operations, I'm not aware that there is any frozen used for commercial herds.

If sexed semen ever gets economical for commercial hogs I'm all for it.    Gilts are ~50% of the population in any given hog building and cause about 90% of the headaches.   Not to mention they grow slower.

I'm not so sure the help at the sow farms is real interested in casterating 2x as many pigs though.