An organization at the forefront of microbiome research, The Morris Animal Foundation provides general information about the microbiome in this article. It is good background information for animal health pros.
Source: Morris Animal Foundation, May 6, 2020. Link. Scientists are just learning how these organisms interact with each other, how they work together to promote the health of the host, and how they restore themselves to balance when disrupted by disease, dietary changes or other external forces.