A major part of animal husbandry is keeping animals healthy and disease-free. With respect to infectious diseases, this largely relies on control of the environment and prompt treatment or culling of infected animals. Until recently, little attention has been paid to the improvement of the genetic robustness or resistance of livestock to infectious pathogens. One reason is the lack of information regarding the genetic contribution of variation in resistance (or susceptibility) to pathogens between animals, and whether such resistance to one pathogen is positively or negatively associated with resistance to other pathogens and to livestock productivity such as growth rate or milk production. A major hurdle in providing this information has been the lack of data collected from animals affected by pathogens and the difficulty in estimating associations between resistance to disease using data from different animals affected by different diseases. Thus, the overall aim and content of this thesis is a comprehensive genetic evaluation of infectious disease traits using all available epidemiological and genomic tools.
