Keywords : Mycobacterium bovis
Iraqi Journal of Veterinary Sciences,
2021, Volume 35, Issue 2, Pages 351-359
A cross-sectional study was carried out from November, 2015 to April, 2018 to determine the prevalence and identify the risk factors of BTB using the comparative intradermal tuberculin (CIDT) test on 5327 dairy cattle in 16 dairy herds in mid-delta, Alexandria Road and Upper Egypt districts. Questionnaires used to collect data on herd size and management. The herd and individual animal prevalence at cut-off ≥4mm were 68.75% (95%, CI: 46 to 91.4) and1.67% (95%, CI: 1.3to 2.1) respectively. The individual prevalence was significantly associated with age, breed and different location of farms and density of cattle in yard. On herd level, history of BTB in the farm, management practices, raising of different species in the same facility and newly purchased cattle are important risk factors for BTB. The postmortem examination of positive reactors revealed 66 (85.71%) out of 77slaughtered cattle with visible lesions and 11(14.29%) with non-visible lesions. Bacteriological examination revealed 74.24% (49/66) from visible lesions and 9.09% (1/11) from non-visible lesions were Mycobacterium bovis. The indirect enzyme linked immunosorbent assay (IELISA) results revealed 31(40.26%) showed positive result including 29 (93.6%) visible lesions and 2(6.4%) nonvisible lesions. In conclusion, the prevalence high in herds with poor management condition, raised different species in the same facility, had previous history of BTB infection and purchased new animals. At animal level Holstein breed, 3-6 years age, kept in high density and located in mid- delta district were at higher risk to be reactor to comparative intradermal tuberculin (CIDT) test.