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Exploratory factor analysis of signalment and conformational measurements in Thoroughbred horses with and without recurrent laryngeal neuropathy
Author(s) -
McGivney C. L.,
Gough K. F.,
McGivney B. A.,
Farries G.,
Hill E. W.,
Katz L. M.
Publication year - 2019
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12984
Subject(s) - medicine , exploratory factor analysis , correlation , rank correlation , analysis of variance , surgery , mathematics , statistics , clinical psychology , geometry , psychometrics
Summary Background Conflicting results have been reported for risk factors for recurrent laryngeal neuropathy (RLN) based on resting endoscopic evaluation and comparison of single conformation traits, with many traits correlated to one another. Objectives To simplify identification of signalment and conformation traits (i.e. variables) associated with RLN cases and controls diagnosed with exercising overground endoscopy (OGE) using exploratory factor analysis (EFA). Study design Prospective cohort. Methods Pearson's rank correlation was used to establish significance and association between variables collected from n = 188 Thoroughbreds from one stable by observers blinded to OGE results. Exploratory factor analysis was conducted on nine variables for cases and controls; common elements between variables developed a factor, with variables grouped into three factors for cases and controls respectively. Correlation (loading) between each variable and factor was calculated to rank relationships between variables and cases/controls, with factors retrospectively named based on their underlying correlations with variables. Results Numerous inter‐correlations were present between variables. Most strongly correlated in cases were wither height with body weight (r = 0.70) and ventral neck length (r = 0.68) and in controls body weight with rostral neck circumference (r = 0.58). Wither height (r = 0.61) significantly loaded the top‐ranked factor for cases (‘height RLN ’), explaining 25% of conformational variance. Ventral neck length (r = 0.69) and age (r = 0.57) significantly loaded the second‐ranked factor for cases (‘neck length RLN ’), explaining 16% of conformational variance. Rostral neck circumference (r = 0.86) and body weight (r = 0.6) significantly loaded the top‐ranked factor for controls (‘body size CON ’), explaining 19% of the variance. Wither height (r = 0.84) significantly loaded the second‐ranked factor for controls (‘height CON ’), explaining 13% of the variance. Main limitations Horses had not reached skeletal maturity. Conclusions Exploratory factor analysis allowed weightings to be determined for each variable. Wither height was the predominant conformational feature associated with RLN. Exploratory factor analysis confirms aggregated conformational differences exist between RLN cases and controls, suitable for future evaluations.