GENETIC-POLYMORPHISM OF MILK-PROTEINS IN POLISH-RED CATTLE - A NEW GENETIC VARIANT OF BETA-LACTOGLOBULIN

Genetic variants of alpha(S1)-, alpha(S2)-, beta- and kappa-casein and of the whey proteins alpha-lactalbumin and beta-lactoglobulin were st udied by isoelectric focusing with carrier ampholytes in milk samples of Polish and German Red Cattle. Genotypic frequencies and allelic fre quencies were estimated. A new beta-lactoglobulin variant (beta-LG I) with a frequency of 0.014 was demonstrated in Polish Red Cattle by iso electric focusing and discontinuous gel electrophoresis. For Polish Re d Cattle significant differences in the allele frequencies from the re sults of 1982 and 1969 were found for alpha(S1)- and kappa-casein and beta-lactoglobulin which are mainly the result of using German Red Cat tle and Red Danish Dairy Cattle during the Fast to improve milk produc tion.