growth promoter (subtherapeutic antibiotic use) but discovered a colistin-resistant form of E. coli bacteria in a pig from a Shanghai farm in 2013. Investigations then led to the identification of "a gene called MCR-1 that allowed bacteria to survive colistin treatment in animals and humans." In 2016, these findings led China to ban colistin as growth promoter. Antibiotics A systematic review found that penicillins and tetracyclines were the most commonly used antibiotics in pigs. Parasites Toxoplasmosis is a constant pressure on pig farming. Worldwide, the percentage of pigs harboring viable Toxoplasma gondii parasites has been measured to be 3-71.43%. Surveys of seroprevalence (T. gondii antibodies in blood) are more common, and such measurements are indicative of the high relative seroprevalence in pigs across the world. Neonatal piglets have been found to suffer the entire range of severity, including progression to stillbirth. This was especially demonstrated in the foundational Thiptara et al. 2006, reporting a litter birth of three stillborns and six live in Thailand. This observation has been relevant not only to that country but to toxoplasmosis control in porciculture around the world. Hygiene Excessively hygienic raising conditions were found to prevent proper gut microbiota development by Schmidt et al. 2011. Moore et al. 1995 describes the pathology of Cryptosporidium infection, a common difficulty in piglet production. In an attempt to curb diseases such as African swine fever, a number of Chinese companies have built condominium-style mega complexes multiple stories high to house thousands of pigs. The buildings have been dubbed "hog hotels" and come with strict protocols and advanced cleaning, veterinary, and disposal systems. However, doubt has been raised by policy specialists and animal scientists over the facilities' efficacy in preventing outbreaks. The welfare of the animals has also been a source of concern, and it has been suggested that the poor welfare of the pigs may cause a decline in their immunity. See also Boar–pig hybrid, Iron Age pig Domestic pig Exotic pet Extensive farming History of animal husbandry Intensive farming Intensive pig farming List of pig breeds Miniature pig Pig toilet Pig slaughter Small Hog Operation Payment Footnotes Further reading J.L. Anderson, Capitalist Pigs: Pigs, Pork, and Power in America. Morgantown, WV: West Virginia University Press, 2019. Livestock Animal husbandry