A systems econometric model of the livestock (beef and pork), poultry (broiler), and corn sectors was estimated to evaluate cross-sector relationships. The equilibrium multipliers and comparative statics indicate unequal cross-effect of market disturbances, e.g., shocks in the livestock and poultry markets impact corn demand and supply more than shocks in the corn market impact livestock and poultry demands and supplies. Recent 2003 mad cow disease (BSE) problems in Canada and the United States display nontrivial cross-effects. For example, the BSE occurrences reduce real corn revenue in the United States by $0.62 billion, or 5.0% of its 2003 revenue.