title: Can you estimate body composition in dogs from photographs?
abstract: BACKGROUND
  A validated method for assessing the visual characteristics of body condition from photographs (vBCS), would be a useful initial screening tool for client-owned dogs.
  
  
  METHODS
  In this retrospective study, photographs taken before and after weight loss from 155 overweight and obese dogs attending a weight management referral clinic were used in designing and testing the feasibility of vBCS. Observers with a range of experience examined the photographs, and estimated body condition indirectly (vBCS) using three different methods. In the first method (vBCSmeasured), the ratio of abdominal width to thoracic width (A:T) was measured, and cut-points used to determine body condition; the second method (iBCSsubjective) involved semi-quantitative examination using visual descriptors of BCS; the third (vBCSadjusted) was a combined approach whereby A:T ratio was first determined, and the final score modified if necessary after assessing photographs.
  
  
  RESULTS
  When an experienced observer performed vBCS, there were moderate-to-good associations between body fat (measured by dual-energy X-ray absorptiometry) and the three vBCS methods (median Rs: 0.51-0.75; P < 0.001), and also moderate-to-substantial agreement with actual BCS (median kappa 0.51-0.63; P < 0.001). For operators with a range of experience, moderate-to-substantial agreement was generally seen between actual BCS and the scores determined by all three methods (median Kappa 0.55-0.70, P < 0.001), but the strength of agreement varied amongst observers. Age, sex, breed, coat length, and coat colour had no significant effect on vBCS (P > 0.05 for all). Compared with ideal weight and obese dogs, errors in assessing body condition were more common for overweight dogs (e.g. BCS 6-7/9, P < 0.001) by vBCSadjusted (P = 0.008), and vBCSsubjective (P = 0.021), but not by vBCSmeasured (P = 0.150). For vBCSadjusted, body condition was most often overestimated whilst, for vBCSsubjective, body condition was most often under-estimated.
  
  
  CONCLUSIONS
  An estimate of body condition can be obtained from an indirect assessment of photographs, but performance varies amongst observers.
authors.affiliation: Department of Obesity and Endocrinology, University of Liverpool, Leahurst Campus, Chester High Road, Neston, Wirral, CH64 7TE, UK.|Present Address: Queen Mother Hospital for Animals, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK.
authors.forename: Poppy
authors.initials: P
authors.lastname: Gant
authors.affiliation: Department of Obesity and Endocrinology, University of Liverpool, Leahurst Campus, Chester High Road, Neston, Wirral, CH64 7TE, UK.
authors.forename: Shelley L
authors.initials: SL
authors.lastname: Holden
authors.affiliation: Royal Canin Research Center, B.P.4-650 Avenue de la Petite Camargue, 30470, Aimargues, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Biourge
authors.affiliation: Department of Obesity and Endocrinology, University of Liverpool, Leahurst Campus, Chester High Road, Neston, Wirral, CH64 7TE, UK. ajgerman@liverpool.ac.uk.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: German
mesh_terms: D000818:Animals; D001823:Body Composition; D004285:Dogs; D005260:Female; D008297:Male; D010781:Photography / Q000662:veterinary*; D012189:Retrospective Studies; D015431:Weight Loss