title: An investigation of ear necrosis in pigs.
abstract: Porcine ear necrosis was investigated in 23 conveniently chosen farms, consisting of 14 case farms and 9 control farms. Biopsies of lesions and oral swabs from pigs on 11 case farms were examined by histology and bacterial culture. All farms were visited for observations and a survey on management, housing, and the presence of other clinical signs or behavioral vices. Histological examination revealed that the lesions began on the surface and progressed to deeper layers, and that vascular damage did not appear to be the initiating cause. Spirochetes were only rarely observed in histological examination and were not cultured from biopsies and oral swabs. Staphylococcus aureus and Staphylococcus hyicus were cultured from 91% and 66% of samples, respectively. Ear biting and a humid environment were associated with ear necrosis. On some farms large numbers of pigs were affected and lesions were sometimes extensive. The condition appears to be an infectious disease beginning on the surface of the skin; contributing environmental and management factors are likely.
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, Guelph, Ontario (Park, Friendship, Poljak, Dewey), Animal Health Laboratory, University of Guelph, Guelph, Ontario (DeLay, Slavic).
authors.forename: Jeonghwa
authors.initials: J
authors.lastname: Park
authors.forename: Robert M
authors.initials: RM
authors.lastname: Friendship
authors.forename: Zvonimir
authors.initials: Z
authors.lastname: Poljak
authors.forename: Josepha
authors.initials: J
authors.lastname: DeLay
authors.forename: Durda
authors.initials: D
authors.lastname: Slavic
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Dewey
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D001522:Behavior, Animal; D001706:Biopsy; D001733:Bites and Stings; D016022:Case-Control Studies; D005260:Female; D006799:Housing, Animal; D006813:Humidity; D008297:Male; D015999:Multivariate Analysis; D009336:Necrosis / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D010032:Otitis Externa / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000473:pathology