The genotype assessment by the CSN3 and LGB genes, affecting the synthesis of milk protein and fat in the milk of Simmental cows
The article presents preliminary results of a study on the influence of the CSN3 and LGB genotypes on milk yield and milk composition. It has been established that for the CSN3 locus, higher milk production rates of cows are associated with genotypes AA and AB. Homozygous BB genotype in cows negatively correlates with milk yield. The percentage of fat in milk is positively affected by the AA genotype. It was also found that the genotypes AA and AB are negatively correlated with the percentage of protein in milk compared to the BB genotype. For the LGB gene locus, the AB genotype was positively associated with milk yield. A significantly higher fat content was recorded in the homozygous BB genotype. The percentage of protein in milk is negatively associated with the LGB genotype. No significant differences between the three genotypes were detected. The effect of individual genotypes of Simmental cows on milk quality has been proven. Knowledge of the genetic structure of dairy cows allows the introduction of modern and fast methods in genetic improvement programs that will increase the efficiency of dairy farms and can be used in future breeding programs using genetic markers.