Study on the polymorphism of bovine lactoferrin gene and its relationship with mastitis.

Mastitis is a major cause of economic loss to the dairy industry. Lactoferrin (Lf) is known to contribute to resistance against bacterial infections. Hence, we decided to characterize the relevance between mastitis resistance and the variants of Lf gene. By using PCR-SSCP, five fragments within 5' region and all exons of bovine lactoferrin gene were amplified and identified the nucleotide diversity. For the five segments within the 5'-region: Lf5'-1, Lf5'-2, Lf5'-3, Lf5'-4, and Lf5'-5 from upstream to downstream, we found that three had base variation. Totally, mutations were observed in Lf5'-1, Lf5'-3, and Lf5'-5, exons 4, 8, 9, 11, 15, and intron 4. We analyzed the effects of all mutated loci on milk production traits with least squares method.