β-defensins: An innate defense for bovine mastitis.

Immune challenges are inevitable for livestock that are exposed to a varied range of adverse conditions ranging from environmental to pathogenic stresses. The β-defensins are antimicrobial peptides, belonging to "defensin" family and therefore acts as the first line of defense against the major infections occurring in dairy cattle including intramammary infections. The better resistance to mastitis displayed by Bos indicus is implicit in the fact that they have better adapted and also has more sequence variation with rare allele conserved due to lesser artificial selection pressure than that of Bos taurus. Among the 58 in silico predicted β-defensins, only a few have been studied in the aspect of intramammary infections. The data on polymorphisms occurring in various β-defensin genes is limited in B. indicus, indicating toward higher possibilities for exploring marker for mastitis resistance. The following review shall focus on concisely summarizing the up-to-date research on β-defensins in B. taurus and discuss the possible scope for research in B. indicus.