科研之友
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摘要
The aim of the present paper was to determine whether there exists an association between the infection by Mycobacterium avium subsp. paratuberculosis (MAP) in cows and the MAP status of their mothers (determined by antibody ELISA and fecal culture). 404 Holstein cows were surveyed. The study was carried out on 75 farms. A total of 202 animals were selected to form the "exposed group". Such animals had been born to dams which had previously tested positive in an antibody ELISA, some of which (n = 42) had positive fecal cultures. An equal number of daughters (paired by age and herd) were included in another group, designated as the "potentially exposed group". The total of these animals had been born to seronegative dams. Both groups were monitored over their first 5 years of life. Two survival models were used to assess the association between the dams' MAP infection status and that of their offspring. The results indicated that the risk of seroconversion was twice as high among the daughters born to dams which had had positive results in both tests: ELISA and fecal culture, in relation to those born to ELISA positive and culture-negative dams and 1.5 to 1.6 times higher in relation to daughters born to both ELISA and culture-negative dams. Eleven daughters from the,exposed group' tested culture-positive, whilst none of the animals from the,potentially exposed' group were found culture-positive throughout the study period. The study detected a relation between dams' and daughters' infection status. Besides, such relationship was first noticed once these daughters had been reared (around the first parity).
- 出版日期2017-4
