Association of beta-lactoglobulin polymorphism with milk production traits in cattle

The study was carried out in Sahiwal, Holstein Friesian, Jersey and crossbred cattle to find out the effect of genotype of beta-lactoglobulin gene on milk production traits. The polymorphism at beta-lactoglobulin gene was identified by conducting PCR-RFLP studies. A 398 bp fragment of the gene was amplified and digested with Hae III restriction enzyme. The two alleles A and B and three genotypes AA, AB and BB were identified in all cattle breeds. The frequency of B allele was comparatively higher than that of A allele. The AA genotype produced significantly higher milk yield in Sahiwal cattle whereas BB genotype yielded higher milk in Holstein friesian cattle. In other cattle breeds the genotypic effect was non-significant. In conclusion it may be stated that the genotype with significantly higher milk yield may be favoured in the farm along with other conventional selection criteria to enhance the milk production of animals.