Characterisation of Mannheimia spp. strains isolated from bovine nasal exudate and factors associated to isolates, in dairy farms in the Central Valley of Mexico.

Abstract Mannheimia spp. strains obtained from bovine nasal exudates of either clinically healthy or clinically affected by respiratory tract disease animals were isolated and characterised to estimate the prevalence of isolated serotypes in dairy farms in Mexico, by means of a trans-sectional descriptive study. Strains were isolated and typified through biochemical and immunological tests. χ 2 or Fisher statistical tests were applied, as well as odds ratio calculation and logistic regression analysis to evaluate the association and effect of some variables on Mannheimia spp. isolation. The apparent prevalence rates of Mannheimia haemolytica was significantly higher in diseased bovines (OR = 1.94; p p p M. haemolytica and Mannheimia glucosida isolates.