GENETIC POLYMORPHISM AT THE K-CASEIN LOCUS IN A DAIRY HERD OF ROMANIAN SPOTTED AND BROWN OF MARAMURES BREEDS

Caseins are a family of milk proteins that exist in several molecular forms and arethe main proteins present in the bovine milk. Genetic variation of these proteins hasbeen associated with the quality and quantity of cheese derived from milk.This study was focused on possibilities to evaluate the frequency of the K-casein Ballele in dairy herds from the Research and Development Station for Bovine RaisingArad in order to have breeding programs that target an increase in the frequency ofthe B allele in the dairy cattle population.In order to differentiate the favorable genotype for superior composition and highercheese yield, we used simple DNA extraction method from fresh blood andtechniques based on DNA analysis, which include polymerase chain reaction andrestriction fragment length polymorphisms (PCR-RFLP) methods. Employing thesetechniques we were able to determine the k-casein genotype of all individuals in agiven population under selection, regardless of sex, age or physiological stage.As a result, it is now possible to include information on milk protein genotypes intomarker assisted selection programs and consequently improve response to selection.