Non-invasive determination of body composition in pigs using a Norland XR-26 bone densitometer

Non-invasive measurement of body composition provides advantages in growth studies compared to conventional techniques. The same individual can be measured several times, the measurement is faster, and the number of pigs required as well as the random effect of animal are reduced. The aim of the present study was to determine the composition of the half carcass and of the ham/shank region by a whole body dual-energy X-ray absorptiometry (DXA) scan of the live pig using a Norland XR-26. Accuracy and precision of DXA measurement were evaluated by regression analysis between DXA-derived values and chemical analysis as well as dissection. Pigs of different gender were used covering a wide range of body weights and body composition. Single regression analysis for lean and fat mass revealed a close relationship between half carcass DXA and chemical analysis (R2 = 0.97 and R2 = 0.91, respectively) as well as dissection (R2 = 0.99 and R2 = 0.98, respectively). The prediction accuracy (R2) was lower for the tissue percentages than for the respective tissue masses. The relationship between live pig DXA and reference methods was close for dissected lean meat (R2 = 0.90) and adipose tissue mass (R2 = 0.93). For chemical lean and fat mass, R2 were slightly lower. Multiple regression analysis using one to four independent variables improved accuracy of prediction. The composition of ham and shank could be predicted more accurately than the half carcass composition.