selection (GS). Genomic selection incorporates genomic information with phenotypic information
(breeding values) to derive genomic estimated breeding values (GEBV) and leads to an increased rate of genetic improvement. The primary principle underlying the application of genomics is that it has the most value for difficult and expensive to measure traits. Maintenance of health will be one of the biggest challenges for efficient livestock production in the next few decades. This challenge will only increase in the face of demand for animal protein, resistance to existing drugs, and the pressure to reduce the use of antibiotics in agriculture. There is probably genetic variation in susceptibility for all diseases but little has been done to make use of this variation to date. In part this is because it is very difficult as well as expensive to measure this variation. This suggests that genomics should provide one of the ways of tackling the challenge of improving animal health .