Effect of Polymorphic Milk Protein Genes on Milk Yield and Composition Traits in Limonero Creole Cattle

In order to characterize the gene of the milk protein k-casein (k-CN) and beta-lactoglobulins (BLG) and determine the association between these on production and milk composition in the Creole Limonero cattle, it was used the Polymerase Chain Reaction - Restriction Fragment Length Polymorphism technique (PCR-RFLP) in 50 cows in production of the Carrasquero local station of National Institute Agricola (INIA-ZULIA). Genotypes were determined by agarose gel electrophoresis. The frequencies obtained from the locus of k-CN were A (0.41) and B (0.59) and genotypic frequencies were AA (0.10), AB (0.62) and BB (0.28), while BLG frequency were BLG A (0.21) and B (0.79) with genotypic frequencies of M (0.06), AB (0.30) and BB (0.64). These results showed that the population studied is in Hardy-Weinberg equilibrium (P<0.05), observing that B allele frequency was higher than that of A in both cases, with respect to k-CN and BLG haplotypes found the same effect (P<0.05) on total solids percentage ( % TS), protein (% PT), fat (% GS), casein (CN%) and total milk production (Ptotal Kg / L), determining that a selection for haplotypes AAAB, AABB and BBAA is appropriate for increasing the%TS, GS, and PT in the Creole Limonero population, thus improving the quality of milk and allowing a higher yield in cheese production, while a selection for the haplotype ABAA increase milk production in the herd. These results represent an important contribution to the knowledge of the breed and its importance as an alternative for cheese production systems.