The objective of the study was to determine the relationship between polymorphism in the RYR1 gene (rs344435545) and on-farm test results (fattening, slaughter and reproductive traits) of pigs maintained in conservation herds. the experiment covered 76 boars and 291 gilts kept in 33 herds. animals aged 150–210 days were weighed and P2 and P4 backfat thickness as well as P4 loin muscle depth (P4m) were measured with an ultrasonic device. standardised daily gain (g/day) of the animals and carcass meat percentage (%) were determined. the following reproductive traits of sows were also collected: number of teats, age at first farrowing, dates of next farrowing, number of piglets born alive and weaned at 21 days of age. Hair roots were sampled from the gilts, sows and boars to determine the RYR1 gene polymorphism. it was found that only 3% of the animals in the analysed population had TT genotypes, whereas 28.34% were heterozygous (CT). this polymorphism (CT) was carried by 28.34% of the animals. when analysing the effect of this polymorphism on fattening and slaughter traits in live animals, it was found that sows with TT genotype, compared to the others, were characterised by higher backfat thickness only (P≤0.05). In the boars with CC and CT genotypes, no significant differences were noted between the values of the analysed traits. for reproductive traits of the sows, it was observed that females with TT genotype weaned more piglets until 21 days of age (P≤0.05).
