The use of dual-energy X-ray absorptiometry to estimate the dissected composition of lamb carcasses

A total of 140 male and female Dorset and Suffolk lambs were slaughtered according to four live weight classes (36–39 kg, 41–44 kg, 46–49 kg and 51–54 kg). Total tissue, fat and lean masses, and bone mineral content measured by dual-energy X-ray absorptiometry (DXA) were used to predict dissected tissue weights. The DXA total weights accurately predict half-carcasses and primal cuts weights (shoulder, leg, loin and flank) (R2 > 0.99, CVe < 1.3%). The prediction of the half-carcass dissected fat percentage is weaker (R2 = 0.77, CVe = 10.4%). Fatness prediction accuracy is equivalent for the shoulder, leg and loin (R2 between 0.68 and 0.78, CVe between 10% and 13%). The R2 obtained when predicting dissected lean content from DXA variables is 0.93 for the half-carcass and higher than 0.83 for all cuts other than flank (CVe are between 3.5% and 6.5%, except for the flank, which is 9.1%). The prediction of bone weight using the bone mineral content is not very accurate for the half-carcass, shoulder and leg (R2: 0.48, 0.47 and 0.43; CVe: 10.2%, 12.0% and 11.6%, respectively). The situation improves, however, for the loin (R2 = 0.70, CVe = 10.7%). In conclusion, DXA is an effective technology for predicting total weight and the amount of lean and fat in lamb carcasses and their primal cuts.