The study included 201 offspring (108 castrated males and 93 females) of
Landrace (L), Large White (LW) and Pietrain (P) sires. The studied animals
were of following genotype: Landrace (L; n = 48); two breed crosses with
50:50 share of parental breeds (LWxL, n=32; and PxL, n=23), two breed
crosses with 75% of paternal breed [Lx(?LWxL), n=35] and [LWx(?LxWL) n=38]
and three breed crosses [Px(?LWxL) n=25]. Animals included in this study
were born during four seasons: winter (n=38), spring (n=65), summer (n=40)
and autumn (n=58). Studies have shown that, at an average weight of warm
carcass side of 81.20 kg, the highest average values for the weight of round
(RW; 10.204 kg), the weight of intermuscular fatty tissue (RINT; 0.478 kg),
bone tissue (RBT; 0.850 kg) and muscle tissue (RMT, 7.552 kg) in the round,
were established in three-breed crosses of Px (LWxL) genotype compared to
other genotypes. The least skin and subcutaneous fatty tissue (RST; 1.269
kg) was recorded in two breed crosses PxL. They had less skin and
subcutaneous fatty tissue by 454 g and 467 grams, respectively, compared to
two breed crosses (LWxL) and LWx (?LxLW). Research has shown that there is a
genotype on a farm that gives more muscle tissue in the round by 1.521 kg
[Px (?LWxL): LWx (?LWxL)] with the same weight of warm carcass side, which
is a very large difference. With the same average weight of warm carcass
side, female animals had higher average weight of the round and yield of
muscle tissue compared to male castrated animals. The effect of genotype
(P<0.001) on all investigated traits was recorded, also the effect of the
season of birth on the skin and subcutaneous fat tissue and on the weight of
intermuscular fat in the round was recorded. The effect of sex/gender was
significant (P<0.01) on the weight of skin and subcutaneous fat and on the
weight of the muscle tissues in the round but no significant effect on other
tested properties (P> 0.05) was observed.