Phenotypes, Genotypes and Allele Frequencies of B-lactoglobulin in Egyptian Cattle and Buffalo

b-lactoglobulin (B-LG) is the major whey protein and its polymorphic gene affects economical traits in cattle breeds. The present study aims to identify the phenotype, genotype and allelic frequency of B-LG gene among local cattle breeds and Buffalo in Egypt, as the phenotyping and genotyping of that gene have not been extensively studied yet in these breeds. Milk samples from Holestien, Baladi cattle and buffalo were assayed for phenotyping of B-LG as well as well as some milk protein traits. Genotyping of B-LG was performed by PCR-RFLP using Hae III endonuclease digestion of a 262 bp PCR products of exon IV and intron IV. The most frequent phenotype in Holestien cattle , Baladi cattle and Buffalo was the BB variant. AA, AB and BB genotypes were existed in Holestien cattle, meanwhile AB, BB and BC genotypes were present in Baladi cattle and Buffalo breeds in Egypt with the predominance of BB genotype in the three breeds. The Holestien cattle populations were in Hardy-Weinberg equilibrium while the Baladi cattle and Buffalo were rejected. The allelic frequency of A, B and C alleles were in the order of 0.205, 0.795 and 0.000 for Holestein cattle, 0.109, o.869 and 0.022 for Baladi cattle and 0.055, 0.917 and 0.028 for Buffalo. The existence of rare BC genotype and the inbred nature were the most interesting result in the Baladi cattle and Buffalo. These results could be included into marker assisted selection programs to improve response to selection in these local breeds.