Genotypic and allelic frequencies of CSN3 and Lactoglobulin B genes in a Creole cattle herd in Argentina

[paper presented at the Ibero-American Symposium "Conservation of Zootechnical Resources"]

Abstract

The Creole cattle in Argentina is well adapted to different environments and its genetics variability become a valuable genetic resource to implement breeding programs. The effects of milk proteins allelic variants on rheological and yield cheese is well documented in cattle. In this paper we describe the genotype and allelic frequencies of K casein (CSN3) and 8 Lactoglobulin (ß-Lg) and we simulate th allelic frequencies changes in five years after a assortative mating system. The DNA of 89 cows was extracted by conventional methods and the PCR-RFLP technique was used to genotype animals. The allelic frequencies for CSN3 gen were: A (0,70), B (0,30) and for ß-Lg gen A (0,36) and B (0,64). After five years by assortative mating with CSN3 B/B bulls and 10 % of replacement with B/B heifers the CSN3 allelic frequencies will be A=0,08 y 8=0,92. Assuming that the CSN3 B allele increase the yield cheese about 5% the net yield after five years with this scheme, the cheese yield could be increased to 3,1 %.