Osteoarthritis of the temporo-mandibular joint in free-living Soay sheep on St Kilda

Colin Arthur, Kathryn Watt, Daniel H. Nussey, Josephine M. Pemberton, Jill G. Pilkington, Jeremy S. Herman, Zena L. Timmons, Dylan N. Clements, Philip R. Scott*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Osteoarthritis (OA) is a common degenerative disease of synovial joints with the potential to cause pathology and welfare issues in both domestic and wild ruminants. Previous work has identified OA of the elbow joint in domestic sheep, but the prevalence of OA of the jaw and in particular the temporomandibular joint (TMJ) has not been previously reported. Following up a previous report of a single case of TMJ OA in a free-living population of Soay sheep on St Kilda in the Outer Hebrides, an archive of 2736 jaw bones collected from this population between 1985 and 2010 was surveyed. Evidence of TMJ OA was found in 35 sheep. Of these, 15 cases were unilateral (11 right side, 4 left side) and the remaining 20 were bilateral. TMJ pathology was much more common in females than males: only 3/35 cases were in males, with overall prevalence at 2.3% for females and 0.2% in males. Radiographic examination of TMJ with OA revealed extensive bone re-modelling with osteophytosis, particularly of the condyle of the mandible. There was a highly significant age-dependence in TMJ OA incidence among age classes: 30/35 cases occurred in geriatric sheep (aged 7 years or more; 11.1% prevalence within this age class), four in adults (2-6 years old; 0.9% prevalence), one in yearlings (0.3% prevalence) and none in lambs. The low incidence in males was confounded by sex differences in longevity: while 18% of females sampled died in the geriatric age class, only 2% of males did so. Although the low prevalence of the pathology limited the ability to test its association with other traits, it was possible to examine relationships with reproductive performance measures amongst geriatric females with and without TMJ OA. Although there were trends towards lower fecundity and lower lamb birth weight in the breeding season prior to death, these were not statistically significant.

Original languageEnglish
Pages (from-to)120-125
Number of pages6
JournalVeterinary Journal
Issue number1
Early online date23 Oct 2014
Publication statusPublished - Jan 2015

Keywords / Materials (for Non-textual outputs)

  • Osteoarthritis
  • Radiography
  • Sheep
  • St Kilda
  • Temporo-mandibular joints


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