In modern, high-density production systems, swine live surrounded by pathogenic microorganisms - bacteria, viruses, and parasites that can cause infectious disease or pathology. Nonetheless, pigs become ill relatively infrequently because they are equipped with a highly evolved immune system that affords protection against infectious microorganisms. This protection can be costly, however, as a number of studies have established that animals reared in unsanitary environments that afford a high level of host-pathogen interaction grow more slowly and consume less feed than animals reared in more sanitary environments (Coates et al., 1963; Roura et al., 1992; Williams et al., 1997b). The view is that nutrients that might have otherwise gone to support growth are redirected to support the host’s defenses against pathogenic microorganisms.
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)