Comparison of host-, herd-, and environmental-factors associated with serpositivity to neospora caninum among adult beef and dairy cattle in alberta

This study represents an analysis of serological and risk factor data collected previously in Alberta, Canada, involving neosporosis in beef and dairy cattle. The causative agent of neosporosis, Neospora caninum (NC), is a single-celled, apicomplexan protozoan parasite in which domesticated dogs have been identified as the definitive host. The primary economic impact involves beef and dairy cattle due to associated abortions and neonatal mortality. The data used in this study were collected for cattle in both dairy and beef herds in an identical manner permitting a direct comparison of host-, herd-, and environmental risk factors for neosporosis among beef and dairy cattle using descriptive statistical methods and the construction of multivariable models. The outcome assessed in the multivariable models was cow-level seropositivity for antibodies to N. caninum. Individual-level fixed, herd-level fixed, and random effects were evaluated with respect to the outcome. In the final multivariable models, there were few statistically significant potential risk factors identified. In the beef multivariable model, the significant explanatory factors were related to acreage of farm, site of calving, and pH of soil. Among the potential risk factors identified in the three multivariable models it appeared seropositivity to NC among beef cattle is more related to environmental conditions; on the other hand, it seems that seropositivity to NC in dairy cattle pertains to associated management factors. In the future, longitudinal studies are needed to explore the validity of the current knowledge regarding N. caninum by investigating potential risk factors that have been identified due to the fact that crosssectional studies can not prove association.