In this study, SNPs linked to mastitis resistance/susceptibility were discovered in the RASGRP1, NFkB, CHL1, MARCH3, PDGFD, MAST3, EPS15L1, C1QTNF3, CD46, COX18, NEURL1, PPIE, and PTX3 genes by PCR-DNA sequencing in Holstein and Montbéliarde cows with and without mastitis. This evidence concerns the gene MAST3 and mastitis.