Effect of maternal separation and transportation stress on the bovine upper respiratory tract microbiome and the immune response to resident opportunistic pathogens

Abstract Background The bovine upper respiratory tract (URT) microbiome includes opportunistic pathogens that cause disease and stress associated with maternal separation transportation contributes to the severity of this disease. Stress is known alter gut but little regarding effect on URT microbiota. This study used six-month old suckling beef calves investigate whether (weaned), by itself or combined (weaned + transport), altered host immune responses resident pathogens. Results Taxonomic functional composition in weaned did not change significantly when serially sampled over a one-month period. Subtle temporal changes were observed transport calves. Total bacterial density was lower ( p < 0.05) day 4 post-weaning both groups compared In addition, significant pathogens, M. haemolytica P. multocida , independent treatment these correlate increased serum antibody bacteria groups. Serum My. bovis another pathogen, remained unchanged all Weaning, combination transportation, also had short- (2 8 days post-weaning) long-term (28 effects expression adrenergic receptor genes blood leukocytes age-matched Conclusions Maternal (weaning) has minor taxonomic pathogen residing bacteria. Significant following weaning, without suggests neuroimmune regulation should be further investigated as mechanism which can host-microbiome interactions for some reside URT.