Bacteriological, Mycoplasmal, Virological and Pathological Studies on Mortalities in Imported Cattle
M ortalities in two imported Frisian cattle herds were investigated within twomonths after arrival in governmental quarantine at Suez governorate in 2006and 2007.The mortality rate was 8.34% in herd (1) 9.02% in herd (2) respectively. Thediseased animals in the two herds showed respiratory manifestations, lacrimations,ptyalism, mucopurulent nasal discharges, depression recumbency, anorexia and profusewatery diarrhoea.The dead calves were necropized, gross lesions were reported and tissuespecimens from internal organs were selected as well as nasal, ocular and rectalswabs were obtained from the diseased animals for histopathological, virological,bacteriological and mycoplasmal studies. Moreover, serum samples and blood sampleson anticoagulant were collected from diseased and apparently healthy animalsfor virological and serological identification.On virological studies, AGPT and commercial ELISA kits were rapid and accuratetests for detection of BVDV antigen. BVDV was isolated on MDBK cell linefrom buffy coats, nasal swabs and rectal swabs collected from diseased calves andfrom internal organs of dead ones, and was identified by IFAT using reference antisera.Also 64 serum samples collected from apparently healthy and diseased calveswere tested by VNT for the detection of neutralizing antibodies against BVDV.Moreover, the lungs, livers, kidneys of dead calves as well as nasal swabs ofdiseased ones yielded Mannhemia haemolytica on bacteriological investigation. Theisolated strains were biotyped to biotype A ( 69 isolates) and biotype B (6 isolates).On virulence test, most M. haemolytica isolates were highly pathogenic for mice,where mortality occurs within 12-48 h. Meanwhile, the resistance of the isolates tomost antimicrobial agents was high (resistant to ceftiofur, nalidixic acid, oxyteteracycline,cephaloridine, gentamicin, cephalexin and donax and highly sensitive tonorfloxacin, ampicillin and erythromycin).Meanwhile Mycoplasma bovis were recovered from trachea, lungs, and liversof dead calves and nasal swabs of diseased ones.