Epidemiology of bovine brucellosis in the Mexicali Valley, Mexico: results of path analysis.

Twenty-eight known or hypothesized variables in the epidemiology of bovine brucellosis were examined by path analysis to determine the contribution of each variable to seropositivity of cattle in Mexicali, Mexico. The variables that contributed significantly to bovine seropositivity were area size of farm premises, percentage of animals on a premises that were inseminated artificially, local marketing of the products from a premises, size of investment in the livestock, whether or not dairying was the major agricultural activity of the premises, and the policy of the owner or manager with regard to disposal of reactor animals. The contributions of all other variables were insignificant.