Identification of β Casein Genotypes in Indian Gir and Crossbred Exotic Cows from Mumbai Dairy Farms

Abstract

Background: Collective evidence of polymorphic β-casein and associated health problems has led to the concern about milk consumption and cow breeding policies worldwide. This association has also engrossed the interest of dairy scientist and industry in evaluation of β casein genotype distribution. With increasing proportion of exotic and crossbred cows in India it is worth while to screen cattle for A1A2 β casein and enhance indigenous cow breeds. Methods: The present study intended to identify β casein genotypes in pure Indian Gir cows and crossbred Holstein and jersey cows from three local dairy farms. We analysed β casein genotypes by PCR-RFLP method in total 95 cows during the period of 2017-2019. Result: All the indigenous Gir cows had fixed A2 allele whereas crossbred Jersey and Holstein Frisian both had A1A2 as the most common genotype (frequency: 0.473 and 0.6 respectively) followed by A2A2 (Frequency 0.368 and 0.333 respectively) and A1A1 (Frequency 0.158 and 0.066 respectively). The results show that in this study group Gir, a native Indian breed has fixed A2 β casein variant whereas crossbred Jersey and Holstein Frisian have A1A2 as a most common genotype. Screening of cattle for â casein genotypes is vital to monitor the frequency of A1 beta casein in native Indian cow breeds.