Abstract
The study was conducted in the Arkhangelsk region using a sample of 430 Kholmogory cows. The aim of this study was to investigate associations between polymorphisms in the mannose-binding lectin (MBL1) gene and milk productivity traits. The samples of DNA were analyzed using PCR-RFLP method with the HaeIII restriction enzyme to identify MBL1 allelic variants: TT (255 bp), TC (255, 178, and 77 bp), and CC (178 and 77 bp). Statistical analysis was performed using the MannWhitney U test (p<0.05). Genotype distribution in the sample was as follows: CC – 26.98 % (116 animals), TC – 50.70 % (218 animals), and TT – 22.32 % (96 animals). The analysis revealed significant superiority of CC genotype cows in milk fat content, averaging 3.75 % for the population. This value was 0.06 % higher than in TC genotype (3.69 %) and 0.15 % higher than in TT genotype (3.60 %), with statistically significant differences confirmed. These results justify incorporating MBL1 gene polymorphism analysis into Kholmogory cattle breeding programs, with particular emphasis on selecting CC genotype animals for nucleus herds. To comprehensively improve the production traits, it is recommended to combine selection for the C allele with milk productivity indicators. A promising direction for further research involves studying MBL1 interactions with other genes affecting milk synthesis and disease resistance, which would enable development of more effective genetic improvement strategies for northern Russian regions. Implementation of these findings in breeding practice will optimize herd management and enhance economic efficiency of dairy cattle farming.