RESUMEN
Canine obesity is a prevalent disease, but many owners are unaware of it, partly due to misperception of their dog's body shape. Body condition scoring (BCS) is a simple method of assessing body composition, but whether it can reduce owner misperception is unclear. Our aim was to determine the effect of a BCS system on owners' ability to estimate the body condition of their dog. Information from 110 dog owners attending three UK veterinary practices was gathered, by interview, between March and April 2013. First, owners were asked to determine their dog's body condition without guidance, and then reassess it using a five-point BCS chart. Most owners (85/110, 77 %) believed the chart to have improved their ability to estimate the condition of their dog correctly. However, only a weak agreement existed between owner estimates and those of the primary investigator, both with (kappa (κ) = 0·28; P < 0·001) and without (κ = 0·32; P < 0·001) the BCS chart. Furthermore, most owners incorrectly estimated their dog's body condition, both with (71/110; 64 %) and without (72/110; 65 %) the chart (P = 1·00), with underestimation being most common (with = 63/71, 89 %; without = 66/72, 92 %; P = 0·57). Owners of overweight dogs more commonly misperceived their dog's body condition, both with (BCS 1-3: 5/35, 14 %; BCS 4-5: 64/75, 85 %; P < 0·001) and without (BCS 1-3: 10/35, 28 %; BCS 4-5: 61/75, 81 %; P < 0·001) the BCS chart. Thus, use of a five-point BCS chart does not improve accuracy of owners' perception of their dog's body shape, despite the accompanying perception that it does.