Miniature Pigs, also called mini pig, or Pygmy pig, or teacup pig, are small breeds of domestic pig. There a two types of mini pig: small traditional pig breed like the Vietnamese Pot-Bellied pig, the Choctaw hog and the Kunekune and even smaller newer breeds like Göttingen minipig and Juliana pig.
Small traditional pig breeds can usually be distinguished from other pigs by their pot belly, a swayed back, a chubby figure, a rounded head, a short snout, short legs, a short neck, and a tail with thick hair at the end. These pigs will range in weight from about to .
The even smaller newer breeds have a weight about half of the small traditional pigs. These breeds were bred as laboratory animals or as pets.
History
One of the first new mini breeds was the Minnesota minipig, which was developed in the USA in the 1940s.
In the 1960s, Chinese pigs that grew to be were sent to zoos in Western cities and were used for medical research in the fields of toxicology, pharmacology, pulmonology, cardiology, aging, and as a source of organs for organ transplantation. These comparatively smaller pigs were easier to work with than larger pig breeds, which typically reach weights of .
Beginning in the late 1960s at the Institute of Animal Breeding and Genetics (Institut für Tierzucht und Haustiergenetik) at the University of Göttingen, Germany, the Göttingen minipig was developed by crossbreeding the Minnesota minipig, the Vietnamese Pot-Bellied pig and the German Landrace pig. It is considered the smallest breed of domestic pig in the world.
In the mid-1980s, the Bowmanville Zoo in Ontario imported breeding Vietnamese Pot-Bellied pigs to Canada, which became the foundation for the pot-bellied pig in North America. The breed is known for its small stature, swayed back, and pronounced pot belly. Because of custom laws, only their offspring could be sold in the United States. U.S. zoos were the main target for the piglets, but private owners soon began purchasing them as pets.
Up to five additional imports were made in the following 10 years. To track the pedigrees, the Potbellied Pig Registry Service, Inc (PPRSI) was created to preserve these bloodlines and establish a breed registry in the United States. This registry was dissolved in the late 1990s. Today, most pot-bellied pigs are little to never purebred, as the pure breed is critically endangered.
The Miniature Potbellied Pig Registry Service, Inc (MPPRSI) was established in 1993 to provide a registry for those pigs who were pedigreed in the PPRSI and met the breed standard, when fully grown not being more than tall and weighing under . All of the foundation pigs were dual registered in the PPRSI and MPPRSI.
Medical research
Miniature pigs have been used for medical research, including toxicology, pharmacology, experimental surgery, pulmonology, cardiology, xenotransplantation, orthopedic procedures and aging studies. Mini pigs are mainly used for biochemical, anatomical, and physiological similarities to humans. They are also quick to develop, making it easier to breed and have more genomic background compared to other animal models of toxicology. Today, more than 60,000 pigs are used for scientific research. For example, scientists are working on studying the possibility of utilizing pig hearts for human heart organ transplants, and work has been done to genetically modify the tissues of pigs to be accepted by the human immune system.
As pets
Miniature pigs are commonly kept as pets. Realistic sizes of pigs vary from pig to pig; genetics drives the growth, along with appropriate nutrition and care. Domesticated miniature pigs can vary from to . However, since pigs can breed years before they fully mature, unscrupulous or ignorant breeders may show off parent pigs which are not fully grown themselves and have not reached their full adult size.
Domesticated pigs are often trained to urinate and defecate in litter boxes, which they learn very quickly. Typically, pine pellets or pine shreds are used. They also can be trained on dog pee pads. They can also be trained to ring a bell by a door when they need to go outside.
In the U.S. as well as Canada, laws may vary on if a pet pig can be kept, depending on the location. If there are no laws regarding pet pigs, some areas may consider a pig to be exclusively known as livestock; some towns and cities have ordinances disallowing farm animals within city limits. However, one can petition city councils and have outdated ordinances amended before a pig is introduced into a household, since many ordinances were put into place before the pot-bellied pig was even introduced to the U.S.