Genome wide scan for somatic cell counts in holstein bulls

Mastitis is the most costly disease for dairy production, and control of the disease is often difficult, due to its multi-factorial nature. Susceptibility to mastitis is under partial genetic control and the industry uses indirect selection for decreased concentrations of somatic cells in milk to reduce mastitis.\r\nBackground: Mastitis is the most costly disease for dairy production, and control of the disease is often difficult,\r\ndue to its multi-factorial nature. Susceptibility to mastitis is under partial genetic control and the industry uses\r\nindirect selection for decreased concentrations of somatic cells in milk to reduce mastitis.\r\nMethods: A genome-wide scan was performed to identify genomic regions associated with deregressed estimated\r\nbreeding values (EBVs) for somatic cell counts (SCC) in Holstein bulls. In total 1183 proven bulls of the Italian of\r\nHolstein population, were genotyped with the BovineSNP50 BeadChip (Illumina, San Diego, CA) and a whole\r\ngenome association analysis was performed using the R package GenABEL.\r\nResults: Two chromosomal regions showed association with SCC, a region on chromosome 14 with high\r\nsignificance (P < 5x10-6) and a region on chromosome 6 with moderate significance (P < 5x10-5).\r\nConclusions: Two regions with effects on SCC have been identified with good statistical support. A further study\r\nof these candidate regions will be performed to verify the results and identify the causal mutations.