title: Human-directed aggression in miniature pet pigs.
abstract: OBJECTIVE
  To determine whether associations exist between human-directed aggression and sex, neutering status, age of weaning, the presence of other pet pigs, or the presence of environmental enrichment objects in miniature pet pigs.
  
  
  METHODS
  Internet survey.
  
  
  METHODS
  Responses from 222 owners of miniature pet pigs.
  
  
  METHODS
  Pet pig owners were requested to complete a 48-item multiple-choice and short-answer Internet survey for each pig that they presently owned.
  
  
  RESULTS
  Among 222 surveys that met enrollment criteria, human-directed aggression that occurred on at least 1 occasion was reported in 64% (n = 142) and aggression that occurred once or more per month was reported in 31% (69). No significant differences were found in the prevalence of human-directed aggression among castrated males, sexually intact females, and spayed females. Ages of weaning and neutering and the presence of objects intended to serve as environmental enrichment were not associated with frequency of aggression. A significant inverse association was detected between presence of other pigs in the same household and human-directed aggression, such that 21% (20/95) of pigs that lived with at least 1 conspecific were aggressive on a frequent basis, compared with 39% (49/126) of pigs that lived with no conspecific. A similar inverse association was evident regarding aggression that occurred on at least 1 occasion.
  
  
  CONCLUSIONS
  Results suggested that human-directed aggression is a common problem in miniature pet pigs. The presence of a conspecific can be expected to reduce the likelihood of human-directed aggression.
authors.affiliation: Behavior Service, Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
authors.forename: Valarie V
authors.initials: VV
authors.lastname: Tynes
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Hart
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Bain
mesh_terms: D000367:Age Factors; D000374:Aggression; D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D000829:Animals, Domestic; D001522:Behavior, Animal; D003625:Data Collection / Q000379:methods; D005260:Female; D006801:Humans; D020407:Internet; D008297:Male; D012307:Risk Factors; D012737:Sex Factors; D013245:Sterilization, Reproductive / Q000662:veterinary; D013552:Swine; D013556:Swine, Miniature / Q000502:physiology* / Q000523:psychology*; D014886:Weaning