Study of Backfat Layers of Swine

Abstract

Data from 169 hogs were used to characterize the three backfat layers by live ultrasonic and carcass measurements as well as fat and moisture determinations. The intermediate (second) fat layer increased faster and to a greater thickness than the outer (first) or inner (third) layer in carcasses with thicker total backfat. The third fat layer contained a greater (P<.01) percent of moisture and residue than the first layer, which contained a greater proportion of these two constituents than the second layer. The second fat layer contained a greater (P<.01) percent of extractable fat than the third layer, whereas the first layer was intermediate. These results indicate that the first and second backfat layers, as measured ultrasonically or on the carcass, and the third layer as measured on the carcass, are approximately equal in accounting for variation in indices of carcass merit. The thickness of the third fat layer appeared to change more postmortem than the first and second fat layer. Thickness of the third layer was significantly (P<.05) correlated with marbling scores. Marbling scores were negatively associated with l. dorsi area and yield of lean cuts.