269 Influence of the maternal rumen microbiome on development of the calf meconium and rumen microbiome

The increasing demand for meat and milk products due to the rising population, coupled with limited resources, requires increased efficiency of livestock. The microbiome within the rumen allows ruminant species to convert low-quality forages into volatile fatty acids (VFA) that are absorbed and digested by the animal to be used as an energy source. Understanding the development of microorganisms within the rumen is of interest due to their effects on host health, energy, performance, and efficiency (Flint and Bayer, 2008; Guan et al., 2008). Evidence suggests that colonization of the calf gastrointestinal tract may occur prior to birth due to the presence of bacteria in the meconium (Alipour et al., 2018). In addition, the establishment of the bacterial communities within the rumen occurs sequentially (Jami et al., 2013; Rey et al., 2014); however, little is known about the relationship and influence of the maternal rumen microbiome on subsequent development of the calf rumen microbiome and VFA production. Research in humans (Biasucci et al., 2010) and ruminants (Cunningham et al., 2018) suggests that there is a maternal influence on gut microbiome development, including mode of delivery and nutrition. In addition, microbial populations established early in life have the ability to affect the health and performance of the adult animal, suggesting the potential for programming of the microbiome (Abecia et al., 2013). Thus, we hypothesized that the cow maternal rumen microbiome would influence colonization of the calf rumen microbiome. Our objective was to relate the rumen microbiome of the cow prior to parturition (RFC) and at weaning (RFCw) to the calf’s meconium microbiome (M) and calf rumen microbiome at birth (RFd1), day 2 (RFd2), day 28 (RFd28), and weaning (RFNw).