topics in the current swine commercial industry.Because the tendency of replacement rate has beenincreasing every year (Engblom et al., 2007), selectionof quality pigs should be substantially focused on inorder to acquire healthy pigs and subsequent decentyields. To maximize production targets in moderncommercial piggeries, an evaluation of pigs’ bodycondition has become one of the significant issues to beunderscored. Optimal body condition of the sows notonly signifies welfare improvement, but it is also aprerequisite to attain sufficient productivity, especiallyin high-producing herds (Maes et al., 2004). Moreover,the heritability of backfat depth in pigs is relativelyhigh (h2~0.5) (Li and Kennedy, 1994). Although themeasurement of body condition is consideredimportant, evaluation in an objective way, under fieldcondition, is not easy to perform. Generally, visualexamination, ranging from 1 to 5 according to thefatness of the pigs, is performed to evaluate the bodycondition of pigs. This method can be applied very wellwithin some herds, e.g. outdoor systems. Nonetheless,a number of drawbacks of this assessment areobserved. First, thin sows can possess high amount ofbackfat. Second, it is regarded as an imprecise andsubjective method since the evaluation relies onpersonal scoring skills. Third, less attention is paid tothe evaluation when visual scoring has to be performedin the same herd over time (herd blindness). Last,difficulties of evaluation occur when the herd containsmore than one breed of e pigs due to variation inconformation among breeds (Whittemore andSchofield, 2000).