[Isolation and identification of Pasteurella spp. in the upper respiratory tract of healthy and unhealthy Holstein [dairy calf pneumonia] calves]

ABSTRACT

To compare Pasteurella spp. isolates of the nasopharyngeal cultures in healthy and unhealthy Holstein [dairy calf pneumonia] calves. Case control study. Sixty Holstein calves from two weeks up to six-month-old in dairy farms of Mashhad Suburb were selected. In the affected calves, the clinical findings were recorded and nasopharyngeal swabs were also taken. Apparently healthy calves were chosen from the same farm as control. T-test, Mann-Whitney and chi-square. Clinical findings including respiratory rate, heart rate, rectal temperature, and illness index scores were significantly different between healthy and unhealthy calves [P<0.05]. Differences between the isolation rates of various pathogens from healthy and unhealthy calves were evaluated by contingency table Chi-square analysis. Pasteurella multicida was isolated more frequently from nasopharynx in affected group than in control one [P<0.05]. Mannheimia hemolytica was isolated more frequently in affected ones than controls. However, its difference was not significant [P>0.05]. Results indicate that Pasteurella multicida was isolated more frequently from nasopharynx in affected calves than in control group. However isolation of Mannheimia hemolytica was not strongly associated with respiratory disease