{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T04:06:30Z","timestamp":1790309190096,"version":"4.1.0"},"reference-count":48,"publisher":"Public Library of Science (PLoS)","issue":"7","license":[{"start":{"date-parts":[[2021,7,21]],"date-time":"2021-07-21T00:00:00Z","timestamp":1626825600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>For many years, there has been a trend to breed cats with an increasing degree of brachycephalic head features, which are known to have a severe impact on the animals\u2019 health and welfare. The direct relation between different grades of brachycephaly and their negative implications have not been researched in this species. The aim of this study was therefore to establish correlations between the different grades of brachycephaly and reduced upper respiratory airways, exophthalmos of the eye globes and malalignment of the teeth in Persian cats. Sixty-nine Persian cats of various skull dimensions and ten Domestic shorthair cats were recruited for the study. The cats\u2019 skulls were examined using three-dimensional reconstructions created from Computed Tomography datasets. Brachycephaly was graded using established craniometric measurements (facial index, cranial index, skull index, craniofacial angle). The flow area of the nasal passageways at different locations, the amount of the eye globe not supported by the bony orbit and the axial deviation of the teeth were quantified and evaluated for a correlation with the grade of brachycephaly. The results of this study clearly show that increased grades of brachycephaly in Persian cats resulted in larger extra-orbital parts of the ocular bulbs. The brachycephalic skull dimension also resulted in a lower height of the naso-osseal aperture, while other areas of the nasal airways were not correlated with the severity of brachycephaly. Persian cats showed a significantly increased occurrence of premolar tooth displacement in the upper jaw with increasing brachycephaly grades. It was interesting to note that the measured values had a broad range and values of some individual Persian cats showed an overlap with those of Domestic shorthair cats.<\/jats:p>","DOI":"10.1371\/journal.pone.0254420","type":"journal-article","created":{"date-parts":[[2021,7,21]],"date-time":"2021-07-21T17:40:58Z","timestamp":1626889258000},"page":"e0254420","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":22,"title":["Correlation of brachycephaly grade with level of exophthalmos, reduced airway passages and degree of dental malalignment\u2019 in Persian cats"],"prefix":"10.1371","volume":"16","author":[{"given":"Jana","family":"Sieslack","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniela","family":"Farke","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Klaus","family":"Failing","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin","family":"Kramer","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3481-4737","authenticated-orcid":true,"given":"Martin J.","family":"Schmidt","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2021,7,21]]},"reference":[{"issue":"7","key":"pone.0254420.ref001","first-page":"450","article-title":"Brachycephaly in dog and cat: a \"human induced\" obstruction of the upper airways","volume":"64","author":"GU Oechtering","year":"2010","journal-title":"Pneumologie"},{"issue":"1","key":"pone.0254420.ref002","doi-asserted-by":"crossref","first-page":"12952","DOI":"10.1038\/s41598-019-49317-4","article-title":"Persian cats under first opinion veterinary care in the UK: demography, mortality and disorders","volume":"9","author":"DG O\u2019Neill","year":"2019","journal-title":"Sci Rep."},{"key":"pone.0254420.ref003","volume-title":"The cat: it\u2019s behavior, nutrition & health","author":"LP Case","year":"2003","edition":"1"},{"key":"pone.0254420.ref004","unstructured":"The Cat Fanciers\u2019 Association I. 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