Fat deposition and distribution measured by computer tomography in three genetic groups of pigs

Amounts and proportions of subcutaneous, inter/intra muscular and internal fat depots were quantified by computer tomography (CT) at 10, 25, 50, 85 and 105 kg live weight in each of 141 animals of the three genetic groups: Norwegian Landrace, Duroc and a crossbreed between Norwegian Landrace and a line selected for high backfat and slow growth (LLP). Selection for reduced fat content at slaughter has resulted in earlier maturation of the fat depots (P<0.05). Differences were found between genotypes in fat amounts and distribution from 10 to 105 kg live weight. At weaning, piglets of modern breeds do not differ in total fat amounts from ‘old’ type. Subcutaneous fat depot is the largest one, and is relatively largest at weaning in all three genetic groups. This fat depot is absolutely and relatively largest in LLP (P<0.05). LLP has highest amounts of fat from 50 kg live weight (P<0.01). The efficient, fast growing Landrace breed has relatively high amounts and proportions of internal fat during the whole growth period. Amounts and proportion of inter/intramuscular fat depot appears to be high in the Duroc breed at 85 kg but not earlier.