Growth and Characterization of Individual Backfat Layers and Their Relationship to Pork Carcass Quality

Purdue University 1999 Swine Research Report. Over the past three years, we have observed that pig genotypes differ not only in the total amount of backfat, but also in the relative amounts of the three individual backfat layers – outer, middle and inner (Figure 1). While it is apparent that these layers differ in chemical, structural and textural properties, their relative contributions to carcass quality remain unknown. Furthermore, we have observed the presence of a well-developed (mature) innermost backfat layer to be associated with higher levels of intramuscular fat within the longissimus dorsi. This suggests that marbling is deposited concurrently with the innermost layer. Thus, the presence of a growing innermost backfat layer may be indicative of a developmental and energy state in which a pig deposits intramuscular fat. Monitoring fat depot development may provide insight into the relationships between individual fat layers and carcass quality. In this trial, we describe the growth of individual backfat layers for three genotypes of pigs and will relate the growth of each layer to pork carcass quality.