Benjamin, Lisa A. (2009-08). An Environmental Perspective to Decision-making for the Control of Johne's Disease on Beef Ranches. Doctoral Dissertation. Thesis uri icon

abstract

  • Biosecurity practices for Mycobacterium avium subsp. paratuberculosis (Mptb), the etiologic agent for Johne's disease (JD), are predicated on the fact that fecal-oral is the major route of infection and that Mptb is present in the environment of affected farms. The objectives of these studies were to describe perceived benefits of testnegative Level 4 status in the Voluntary Bovine Johne's Disease Control Program (VBJDCP), describe producer and veterinarian attitudes towards JD relevant biosecurity practices, compare 5 JD control options using a Markov model, determine if tangential flow filtration (TFF) increases the detection sensitivity for Mptb and describe the distribution of environmental predictors for Mptb survival. Twenty-five percent and 39% of beef producers in the VBJDCP reported that they received substantial or marginal benefits (financial and non-financial), respectively, from program participation. Producers suggested increased marketing opportunities to improve the VBJDCP. Producers in a cross-sectional mailed survey of attitudes towards biosecurity practices were more likely than veterinarians to agree that separating JD clinical or suspects from calves or heifers; acquiring replacements or additions from JD low-risk herds, testing for JD every 10 to 14 months and test and culling clinical suspects only were useful for control of JD. A state transition Markov model, with the environment as the source of Mptb, was used to compare 6 alternative control strategies for JD. Management and the probability of Mptb surviving 1 year in the environment were important determinants of the prevalence of subclinical JD on beef farms under the analyzed control strategies. Heterogenous distribution of environmental predictors for Mptb survival was observed in spatial risk maps. In conclusion, although some beef producers experienced gains from participation in the VBJDCP, the perceived program benefits could be improved by increased marketing and education on the advantages of participation. Specific problem areas should be addressed. The length of time Mptb survived in the environment was an important parameter in the Markov chain model. Additionally, due to the heterogenous distribution of environmental predictors, a multiscale approach to sampling and analysis should be useful.
  • Biosecurity practices for Mycobacterium avium subsp. paratuberculosis (Mptb),
    the etiologic agent for Johne's disease (JD), are predicated on the fact that fecal-oral is
    the major route of infection and that Mptb is present in the environment of affected
    farms. The objectives of these studies were to describe perceived benefits of testnegative
    Level 4 status in the Voluntary Bovine Johne's Disease Control Program
    (VBJDCP), describe producer and veterinarian attitudes towards JD relevant biosecurity
    practices, compare 5 JD control options using a Markov model, determine if tangential
    flow filtration (TFF) increases the detection sensitivity for Mptb and describe the
    distribution of environmental predictors for Mptb survival.
    Twenty-five percent and 39% of beef producers in the VBJDCP reported that
    they received substantial or marginal benefits (financial and non-financial), respectively,
    from program participation. Producers suggested increased marketing opportunities to
    improve the VBJDCP. Producers in a cross-sectional mailed survey of attitudes towards biosecurity
    practices were more likely than veterinarians to agree that separating JD clinical or
    suspects from calves or heifers; acquiring replacements or additions from JD low-risk
    herds, testing for JD every 10 to 14 months and test and culling clinical suspects only
    were useful for control of JD.
    A state transition Markov model, with the environment as the source of Mptb,
    was used to compare 6 alternative control strategies for JD. Management and the
    probability of Mptb surviving 1 year in the environment were important determinants of
    the prevalence of subclinical JD on beef farms under the analyzed control strategies.
    Heterogenous distribution of environmental predictors for Mptb survival was observed
    in spatial risk maps.
    In conclusion, although some beef producers experienced gains from
    participation in the VBJDCP, the perceived program benefits could be improved by
    increased marketing and education on the advantages of participation. Specific problem
    areas should be addressed. The length of time Mptb survived in the environment was an
    important parameter in the Markov chain model. Additionally, due to the heterogenous
    distribution of environmental predictors, a multiscale approach to sampling and analysis
    should be useful.

publication date

  • August 2009