Relation of polymorphism of beta-lactoglobulin with chemical compostion in cows milk

Kemijski sastav kravljeg mlijeka pod utjecajem je cijelog niza genetskih i negenetskih čimbenika. Od okolišnih čimbenika na kemijski sastav mlijeka osobit utjecaj ima hranidba, sezona i mikroklimatsko okruženje. Povezanost nasljednih čimbenika sa kemijskim sastavom kravljeg mlijeka počela se osobito istraživati tijekom druge polovice XX stoljeća, nakon otkrića polimorfnih oblika određenih proteina u mlijeku. Uočene određene povezanosti alelnih polimorfnih oblika sa mliječnošću krava, te posebice preradbenom iskoristivošću mlijeka (prinos sirnog gruša, čvrstoća sirnog gruša i drugo) potakle su interes uzgojnih organizacija i mliječne industrije o daljnjem istraživanju veza polimorfnih oblika proteina s kvalitativnim i preradbenim odlikama mlijeka. Razvoj metoda elektroforeze, a posebice neposredne detekcije polimorfizma na odgovornim kodirajućim segmentima gena potakli su daljnja istraživanja povezanosti polimorfizma s bitnim odlikama u proizvodnji i preradi kravljeg mlijeka. U ovom diplomskom radu istražena je povezanost polimorfizma beta-laktoglobulina sa kemijskim sastavom mlijeka simentaskih i holštajn krava u prve tri proizvodne laktacije. U istraženoj populaciji utvrđena su dva genotipa beta-laktoglobulina (AB i BB). Nije utvrđen značajan utjecaj genotipova i alelnih oblika beta-laktoglobulina na kemijski sastav kravljeg mlijeka.Chemical composition of cow`s milk is influenced by a whole series genetic and nongenetic factors. From the environmental factors to the chemical composition of milk, the nutrition, season and microclimatic environment have a particular impact. The correlation of hereditary factors with the chemical composition of cow`s milk began to be particulary explored during the second half of the 20th century, following the discovery of polymorphic forms of certain protein milk. The observed association of allelic polymorphic forms with the cow`s milk, particular the utilization of milk (yield of wheat grain, firmness of wheat grain and other) were the interest of breeding organizations and dairy industry on further investigation of the linkage polymorphic forms of protein with qualitative and processing characteristics of milk. Development of electrophoresis methods, and in particular direct detection of polymorphisms on the responsible coding segments of the gene, stimulated further investigation of the association polymorphism with essential characteristics in the production and processing of the cow`s milk. In thesis deals the association of the beta-lactoglobulin polymorphism with the chemical composition of the Simmental and Holstein cows in the first three lactations production. Two beta-lactoglobulin genotypes (AB i BB) were determined in the investigation population. No significant influence of genotypes and alleles of beta-lactoglobulin on the chemical composition of cow`s milk wasn`t established