Estimating body fat in mature beagle bitches

Body composition was determined in 24 female Beagle dogs ranging in age from 2 to 4 years (live weight 11.1 +/- 3.3 kg). Subcutaneous fat measurements were made using an ultrasonic probe device on the live animal and direct measurements after death. Measurements were made near the shoulder, mid-rib, last rib, mid-lumbar, and last lumbar areas. The actual fat measurement giving the highest correlation with body fat was the one made directly over the longissimus muscle near the last rib (r2 x 100 = 93.6). Multiple linear regression, using live weight and the last rib fat thickness measurement, estimated body fat with a standard error of 0.27 kg (r2 x 100 = 98.4). Body fat = 2.2 + (0.13 x fat thickness + (0.36 x live weight) where body fat and live weight were measured in kg and fat thickness in mm.