The Davison County Commission on Tuesday approved the expansion of Blue Stem Family Farms.  Blue Stem, which is a sow farm managed by Pipestone Veterinary Services of Minnesota, is located three miles north and four miles east of Mount Vernon.  Marty Rost says they are expanding from 5,000 sows to 9,000 sows.  He says the total economic benefit to the region will be over $6 million dollars.