title: Quantitative assessment of increased sensitivity of chronic laminitic horses to hoof tester evoked pain.
abstract: BACKGROUND
  To evaluate quantitative sensory testing (QST) of the feet of laminitic horses using a power-assisted hoof tester.
  
  
  OBJECTIVE
  Hoof Compression Thresholds (HCTs) can be measured reliably and are consistently lower in horses with chronic laminitis than in normal horses.
  
  
  METHODS
  HCTs of chronic laminitic (n=7) and normal horses (n=7) were repeatedly measured using a hydraulically powered and feedback controlled hoof tester. Data from 2 tests, at 3 sites in both forefeet, during 3 sessions were collected and statistically analysed using linear mixed models.
  
  
  RESULTS
  The mean±s.e. HCT for the laminitic horses was 29.6±3.5 kg/cm2 and for horses in the normal group was 59.8±4.3 kg/cm2. Residual variance was the largest of the error components and was greater (P<0.001) for the normal horses; none of the other components significantly differed between the 2 groups. Averaging of HCTs from each foot could produce a test with intraclass correlation coefficients of 0.83 for the normal group and 0.87 for the laminitic group, with an estimated sensitivity of 0.94 and a specificity of 0.93. This test would permit detection with 80% power and 95% confidence of a reduction of over 40% in the difference in mean HCTs between laminitic and normal horses following effective treatment provided that the experimental groups are of 9 or more horses.
  
  
  CONCLUSIONS
  HCTs can be safely and reliably measured experimentally using this hoof tester. The level of variability found indicates that, under these conditions, treatments may need to produce at least a 40% improvement to be detected. Simplification of the hoof tester, training of the horse and repeated testing may permit the method to be used clinically to detect changes in the HCTs of individual laminitic horses but these potential improvements will require further investigation.
  
  
  CONCLUSIONS
  Measurement of HCTs can provide an additional means for assessing the effectiveness of treatments for alleviation of chronic equine laminitis.
authors.affiliation: Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK.
authors.forename: I
authors.initials: I
authors.lastname: Viñuela-Fernandez
authors.forename: E
authors.initials: E
authors.lastname: Jones
authors.forename: I J
authors.initials: IJ
authors.lastname: McKendrick
authors.forename: V
authors.initials: V
authors.lastname: Molony
mesh_terms: D000818:Animals; D002908:Chronic Disease; D005534:Foot Diseases / Q000175:diagnosis / Q000662:veterinary*; D006724:Hoof and Claw; D006734:Horse Diseases / Q000175:diagnosis* / Q000209:etiology; D006736:Horses; D010146:Pain / Q000175:diagnosis / Q000662:veterinary*; D010147:Pain Measurement / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D017288:Pain Threshold