SWINE: DEFINITIONS OF USE CLASSES1 Icon for PDF

Boars Intact male pigs intended for breeding purposes or slaughter.
Barrows Castrated male pigs intended for slaughter.
Gilts Female pigs that have not farrowed a litter and are intended for slaughter or breeding purposes.
Replacement Gilts Female pigs that have not farrowed a litter.
Sows Female pigs that have farrowed one or more litters.
Nursing Pigs (aka suckling pigs, weanlings) Pigs from birth until weaning that are currently nursing.
Starter or Nursery Pigs Boars, barrows, and gilts from approximately 40-70 lb (18-32 kg).
Growing Pigs Boars, barrows, and gilts from approximately 40-70 lb (18-32 kg) to 120-150 lb (55-68 kg).
Finishing Pigs Boars, barrows, and gilts from approximately 120 to 150 lb (55-68 kg) to market weight for slaughter.
1All definitions and descriptions of animal use classes are based on information in Guidance for Industry #191 published by the Food and Drug Administration Center for Veterinary Medicine in May 2015.