The influence of CSN3 and LGB polymorphisms on milk production and chemical composition in Romanian Simmental cattle

The aim of the study was to assess the influences of genotypes from κ-casein (CSN3) and β-lactoglobulin (LGB) loci on milk production and chemical composition in Romanian Simmental cattle. For CSN3 locus a significant increased frequency (P ≤ 0.001) was observed for the allele A (0.785) compared with allele B (0.215) and for AA (0.631) compared to AB (0.307) and BB (0.062) genotypes. The AA genotype was associated with a higher milk production (5887.76±115.7 kg) compared to the yields associated with BB genotype (5619±86.34 kg, P ≤ 0.003) and a higher fat percentage (4.19±0.05% vs. 4.01±0.02%, P ≤ 0.001). A higher milk protein percentage was associated with BB (3.4±0.02%) compared to AA (3.27±0.03) and AB (3.29±0.03) genotypes (P ≤ 0.05). For LGB locus, the frequency of allele A was significantly higher (0.606, P ≤ 0.008) than allele B (0.394). The predominately AB genotype was the most prevalent in herd (0.579) compared to AA (0.316) and BB genotypes (0.105). The AB genotype was associated with a higher milk production (5906.54±166.76 kg) compared with the other two genotypes (P ≤ 0.05). The BB genotype was associated with a higher fat percentage in milk (4.23±0.06%) compared with AA (4.17±0.06) and AB (4.2±0.08) genotypes (P ≤ 0.01). For the LGB locus no significant differences (P > 0.05) were observed for milk protein percentage. The current outcomes encourage improving genetic structure in cattle, based on marker assisted selection for genes with economic values, in order to increase the quantity and quality of milk.