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Home / Equine Research Bank / Vet Ophthalmol / Risk factors for equine recurrent uveitis in a population of...
Veterinary ophthalmology2020; 23(3); 515-525; doi: 10.1111/vop.12749

Risk factors for equine recurrent uveitis in a population of Appaloosa horses in western Canada.

Abstract: To characterize clinical manifestations, measure frequency, and evaluate risk factors for equine recurrent uveitis (ERU) in Appaloosa horses in western Canada. Methods: 145 Appaloosa horses. Methods: Ophthalmic examinations were completed and eyes were classified as having no or mild clinical signs, or moderate, or severe damage from ERU. Clinical signs, age, sex, base coat color, and pattern were recorded. Whole blood and/or mane hair follicles were collected for DNA extraction, and all horses were tested for the leopard complex (LP) spotting pattern allele. Pedigree analysis was completed on affected and unaffected horses, and coefficients of coancestry (CC) and inbreeding (COI) were determined. Results: Equine recurrent uveitis was confirmed in 20 (14%) horses. The mean age of affected horses was 12.3 years (±5.3; range 3-25). Age was a significant risk factor for ERU diagnosis (ORyear  = 1.15) and classification (ORyear  = 1.19). The fewspot coat pattern was significantly associated with increased risk for ERU compared to horses that were minimally patterned or true solids. The LP/LP genotype was at a significantly greater risk for ERU compared to lp/lp (OR = 19.4) and LP/lp (OR = 6.37). Classification of ERU was greater in the LP/LP genotype compared to LP/lp. Affected horses had an average CC of 0.066, and there was a significant difference in the distribution of CC for affected horses versus the control group (P = .021). One affected horse was the sire or grandsire of nine other affected. Conclusions: Age, coat pattern, and genetics are major risk factors for the diagnosis and classification of ERU in the Appaloosa.
© 2020 American College of Veterinary Ophthalmologists.
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Publication Date: 2020-02-22 PubMed ID: 32086865DOI: 10.1111/vop.12749Google Scholar: Lookup
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  • Journal Article
  • Multicenter Study

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The study explores the relation, frequency, clinical symptoms, and risk factors of equine recurrent uveitis (ERU) in a specific horse breed (Appaloosa) in western Canada. According to the research, ERU is significantly influenced by factors such as age, coat pattern and certain genetic components in these horses.

Methodology

  • The study examined 145 Appaloosa horses through detailed ophthalmic examinations. The examinations helped classify the horses into various categories based on the severity of ERU symptoms they exhibited. The classifications ranged from no symptoms to severe damage from ERU.
  • Other data collected includes age, sex, base coat color, and pattern for each horse to evaluate if these factors had any correlation with ERU.
  • In addition to physical examinations and data collection, genetic testing was performed by extracting DNA from the whole blood and/or mane hair follicles of the horses. The testing focused particularly on the presence of the leopard complex (LP) spotting pattern allele.
  • A pedigree analysis was also completed on both affected and unaffected horses. This analysis offered insight on specific coefficients – coancestry (CC) and inbreeding (COI).

Results

  • Out of the total, 20 (14%) horses were confirmed with ERU. The mean age of these affected horses was 12.3 (with a range of 3-25 years), suggesting that age was a significant risk factor for ERU diagnosis.
  • The fewspot coat pattern was identified as another significant risk factor. Horses with this pattern were found to be at greater risk for ERU than those with minimal patterns or true solid coats.
  • The LP/LP genotype presented a greater risk for ERU as compared to lp/lp and LP/lp genotypes. In other words, the genetic component (the LP spotting pattern allele) was a determining factor in ERU risk.
  • The pedigree analysis showed that one affected horse was either the sire or grandsire of nine other affected horses. The CC (coancestry coefficient) of the affected horses averaged at 0.066, indicating a significant difference in the distribution of CC for affected versus non-affected horses.

Conclusion

  • The study concluded that risk factors playing significant role in the diagnosis and classification of ERU in the Appaloosa horses are age, coat pattern, and certain genetic features.

Cite This Article

APA
Sandmeyer LS, Kingsley NB, Walder C, Archer S, Leis ML, Bellone RR, Bauer BS. (2020). Risk factors for equine recurrent uveitis in a population of Appaloosa horses in western Canada. Vet Ophthalmol, 23(3), 515-525. https://doi.org/10.1111/vop.12749

Publication

Veterinary ophthalmology
ISSN: 1463-5224
NlmUniqueID: 100887377
Country: England
Language: English
Volume: 23
Issue: 3
Pages: 515-525

Researcher Affiliations

Sandmeyer, Lynne S
  • Small Animal Clinical Sciences, University of Saskatchewan, Saskatoon, Sask, Canada.
Kingsley, Nicole B
  • Equine Research Unit, University of California Davis Veterinary Genetics Laboratory, Davis, CA, USA.
Walder, Cheryl
  • Large Animal Clinical Sciences, University of Saskatchewan College of Veterinary Medicine, Saskatoon, Sask, Canada.
Archer, Sheila
  • independent Researcher, Sayward, BC, Canada.
Leis, Marina L
  • Small Animal Clinical Sciences, University of Saskatchewan, Saskatoon, Sask, Canada.
Bellone, Rebecca R
  • Veterinary Genetics Laboratory and the Department of Population Health and Reproduction, University of California-Davis, Davis, CA, USA.
Bauer, Bianca S
  • Small Animal Clinical Sciences, University of Saskatchewan, Saskatoon, Sask, Canada.

MeSH Terms

  • Alberta / epidemiology
  • Animals
  • Female
  • Horse Diseases / diagnosis
  • Horse Diseases / epidemiology
  • Horse Diseases / etiology
  • Horses
  • Male
  • Pedigree
  • Recurrence
  • Risk Factors
  • Saskatchewan / epidemiology
  • Uveitis / epidemiology
  • Uveitis / veterinary

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