SWINE: DEFINITIONS OF USE CLASSES Icon for PDF

Boars Intact, sexually mature, male pigs intended for breeding purposes; generally not intended for slaughter in the U.S.
Barrows Castrated male pigs intended for slaughter.
Gilts Female pigs that have not farrowed a little and are intended for slaughter or breeding purposes.
Replacement Gilts Breeding female pigs that have not farrowed a litter; usually weigh 220-300 lb (100-135 kg).
Sows Female pigs that have farrowed one or more litters.
Nursing Pigs Pigs from birth until weaning that are currently nursing.
Starter or Nursery Pigs Boars, barrows and gilts from approximately 2-4 weeks of age and approximately 50-60 lb (23-27 kg).
Growing Pigs Barrows and gilts from approximately 50-60 lb (23-27 kg) to 120-150 lb (55-68 kg).
Finishing Pigs Barrows and gilts from approximately 120 to 150 lb (55-68 kg) to market weight for slaughter.