Minnesota is well represented in the latest annual Pork Powerhouses report in Successful Farming magazine. The ranking of the 25 largest producers includes 7 Minnesota firms and 4 Iowa companies.

The report concluded that three-quarters of these largest pork companies, 19 of 25, added sows in 2014, by purchasing existing farms, building new sow farms, and increasing sow density in existing farms. The overall increase among the largest pork producers was about 3 percent more sows compared to a year ago.

The report also noted "enormous" gains for the biggest hog farms, averaging $82 profit for each hog marketed in the third quarter.

One major reason is tighter supplies of hogs, caused by porcine epidemic diarrhea virus. The disease has killed millions of baby pigs, amounting to 5 percent of supplies by some estimates. Growers have reduced the effect of the losses somewhat by raising pigs to larger weights.

The largest pork powerhouse is Smithfield Foods, owned by the Chinese-based company WH Group, with 887,000 sows. Second on the list is Triumph Foods, a group of several operations that includes Christensen Farms in Sleepy Eye.

Other Minnesota firms on the list: Pipestone System in Pipestone; Cargill, based in Wayzata; Holden Farms in Northfield; Hormel Foods in Austin; Schwartz Farms in Sleepy Eye; and Protein Sources in Mapleton.