Research Regarding Genetic Polymorphism on the Main Lactoproteins at Sură de Stepă Breeds.

Research was carried out on a number of 30 Sură de Stepă cows raised in semi-intensive stalling at S.C.D.C.B. - Dancu, Iasi. On this nucleus we studied the main lacto-proteins systems and the correlations with milk production indicators. At Sura de Stepă breed were identified alleles for the six loci codifying the six types of major milk proteins (α S1-cz; β-cz; K-cz; β-lg; α-la; α S2-cz). In the system αS1-cz allele αs1-Cn B has the greatest frequency (0.700), in the system β-cz allele α-Cn A2 (0.550), in the system K-cz allele k-CnA2 (0.583) and heterozygous genotype AB (0.416) respectively BB (0.375), in the system β-lg allele β-lgA1 has the greatest frequency (0.542) and heterozygous genotype AB (0.500), in the system α-la could be found a mono-morphism for allele α-la B and similar in the system αS2-cz for allele αs2-Cn A. Kappa-casein (K-cz) is positive and strongly correlated with fat % respectively protein % (rp = 0.58-0.77, rg = 0.67-0.83, rm = 0.64-0.87). [ABSTRACT FROM AUTHOR]