Characterization of the Fecal Bacterial Microbiota of Healthy and Diarrheic Dairy Calves

Gomez, D.E.; Arroyo, L.G.; Costa, M.C.; Viel, L.; Weese, J.S.

The gastrointestinal microbiota plays an important role in maintaining host health by providing vitamins and energy, 3 by facilitating development of gut tissue and the immune system, 4 by modulating inflammatory responses at local and distal organs, 5 and by competing with pathogens for nutrients and attachment sites on the gut epithelial surface. 6 Although traditional focus on calf diarrhea has been on individual pathogens, it has become increasingly clear in other species that microbial populations play a key role in health and disease. Disruption of this ecosystem, otherwise known as "dysbiosis," can trigger gastrointestinal disorders. 7 To date, the molecular basis of dysbiosis and the key bacterial groups involved remain poorly defined. It is clear however that if the gut microbiota is disrupted (eg, antibiotic treatment, gut inflammation) the risk of disease can increase substantially [8] [9] [10] and re-establishment of the normal microbiota can result in recovery from disease. 11 Despite current attention and research on the gut microbiota, few population-based studies have been conducted in cattle to better understand how the microbiota and its functional potential are impacted during neonatal diarrhea. Calf diarrhea may be associated with altered microbial diversity and decreased abundance of butyrate-producing microorganisms during the first weeks of life. 12 The gastrointestinal microbiota is a major contributor to the physiological, nutritional, and immunological functions of the gut. Therefore, the structure and functional roles of the microbiota in diarrheic calves should be examined in more detail. The objectives of our study were to profile the fecal microbiota and predict the functional potential of microbial communities in healthy calves and calves with diarrhea from 2 large dairy farms with dissimilar management practices.