Allelic and genotypic frequencies of the Kappa Casein and βeta Lactoglobulin gene in Brown Swiss cattle

Abstract

The Brown Swiss breed is one of the breeds with great genetic development oriented to the production of greater volumes of milk. The objective of this study was to determine the allelic and genotypic frequencies of the Κappa casein and βeta Lactoglobulin gene in cattle with Brown Swiss and Brahaman crosses. 20 female bovine animals were selected, located in the Santa Rosa farm of the Faculty of Animal Science of the National Agrarian University (UNA). DNA was extracted from whole blood with EDTA. DNA was extracted from whole blood with EDTA. With the PCR technique, fragments of the Kappa casein gene of 351 bp and fragments of 262 bp for the Beta lactoglobulin gene were amplified. Genotyping was carried out with the PCR-FRLP technique and the separation of fragments for both genes was carried out on a 2 % agarose gel. The genotype frequencies found for Κappa casein were 0.25 (5/20), 0.65 (13/20), 0.10 (2/20), for the AA, AB and BB genotypes respectively, with the heterozygous AB being more frequent. The allele frequencies for this same gene were 0.575 and 0.425 for alleles A and B. The genotype frequencies for βeta Lactoglobulin were 0.05 (1/20), 0.1 (2/20), 0.85 (17/20) for the AA genotypes, AB and BB respectively, with homozygous BB being more frequent. The allele frequencies were found to be 0.1 and 0.9 for the A and B alleles of βeta Lactoglobulin. The individuals evaluated for Κappa casein presented a low proportion of the desirable BB genotype, while for βeta Lactoglobulin the proportion of individuals with the desirable BB genotype was higher.