Abstract: The present invention relates interactions between genotype and diet that are useful in the dietary control of intestinal disease. Compositions are related that are useful to differentiate, with a high level of sensitivity and specificity, swine that are genetically resistant to a reduced rate of weight gain when fed diets containing high levels of SBM. The reduced rate of gain can be prevented by reducing the levels of SBM in nursery diets and replacing a majority of the soy bean meal with animal-based protein sources, fish meal, plasma or milk. Genetically resistant swine fed either the diet low in SBM, or a diet high in SBM, and susceptible swine fed a diet low in SBM, were not colonized by F18+E. coli and gained weight at an acceptable rate.