Relationships Between Beta-Lactoglobulin and Beta-Casein Polymorphisms and Production Traits in Brown Swiss and Holstein

Abstract

Ozdemir, M and Dogru, U. 2007. Relationships between beta-lactoglobulin and beta-casein polymorphisms and production traits in Brown Swiss and Holstein. J. Appl. Anim. Res., 31: 165–168.

To study the effects of Beta-Lactoglobulin (β-Lg) and Beta-Casein (β-Cn) polymorphism on milk production traits, milk samples from Brown Swiss, Holstein and East Anatolian Red cows were analyzed for β-Lg and β-Cn AA, AB and BB types using horizontal starch-gel electrophoresis method. Differences of both β-Lg and β-Cn among breeds studied in terms of proportion of phenotype were significant on gene variants. While effects of β-Cn phenotypes on studied yield traits were not significant, there was a main effect of β-Lg genotype on fat concentration, actual milk yield, actual fat yield, 305 d fat yield and lactation period in Brown Swiss and Holstein cows, but not on 305-days milk yield. We suggest that production and percentage of fat ratio may be maximized by the use of β-Lg AA genotype and milk production by the use of β-Lg AB genotype with selective goal in herds.

Keywords:

• Beta-lactoglobulin
• beta-casein
• polymorphism
• cow
• production traits
• genetic marker