In an effort to improve pre-harvest traceability and improve national disease surveillance in the pork industry, many major U.S. packers and processors will require a USDA-approved, official premises identification number (PIN) swine tag as a condition of sale for breeding stock beginning Jan. 1, 2015.
Once an animal is identified with an official PIN tag, it should not be removed or given a different official tag in the case of parity-segregated farms. Also, records documenting the identification and movement of breeding stock should be kept for three years.

When ordering tags, producers must provide the nationally standardized PIN for the breeding farm. If the site does not have a PIN, producers can register for one by going to www.pork.org/PINtag.
To date, packers that will require PIN tags as of January 2015 include: Johnsonville, Hillshire Brands, Calihan Pork Processors, Bob Evans Farms, Wampler's Farm Sausage, Pine Ridge Farms, Pioneer Packing Co., Pork King Packing and Abbyland Pork Pack.
Monday November 11, 2013/ National Pork Board/ United states.
http://www.pork.org/