Heritability, phenotypic and genetic correlations of the growth intensity and meat yield of pigs

The five year study included two genotypes of gilts of performance tested gilts, Swedish landrace and crosses F1 generation SLxLY. Of total number (n=3600), 1709 animals were genotype SL and 1891 animals were genotype SLxLY. Measuring of back fat thickness in the loin part (FT1), between 3rd and 4th lumbar vertebrae, 7cm laterally to the back line; back fat thickness (FT2) and depth of the musculus longissimus dorsi (MLD) between the 3rd and 4th rib from the rear, 7cm laterally to the back line. Assessment of meat yield was done using the ultrasonograph apparatus Piglog 105. In regard to meat yield indicators, medium heritability values were established for FT1 h2=0.461, and high values for FT2 h2=0.639, and for meat yield h2=0.633. Low heritability was established for depth of MLD (h2=0.105), life daily gain (h2=0.110) and age at the end of test (h2=0.103). Established phenotypic correlations between fat thickness FT1 and FT2 were strong (rp=0.638); between fat thickness and meat yield very strong (rp=-0.880 to -0.895), and between fat thickness and MLD very weak and negative (rg=-0.103 to -0.216). Genetic correlations were stronger than phenotypic, so between fat thickness FT1 and FT2 the correlation was complete/full (rg=0.930), also between fat thickness and meat yield (rg=-0.979 to -0.982), whereas the correlation between fat thickness and MLD was strong and negative (rg=-0.627 to -0.653). Heritability values for fat thickness and meat yield show that these traits have high level of heritability and are transfered to the progeny, whereas the level and strength of their dependance show that by decreasing the fat thickness positive influences is exhibited on meat yield, and that by increasing of depth of MLD also the meat yield is increased.