The present invention relates to a method to introduce a nucleic acid molecule into a felid by administration of a nucleic acid-cationic lipid complex composition. The method includes the step of administering to the felid, by a parenteral route, a nucleic acid-cationic lipid complex to elicit and/or enhance an immune response. In one embodiment, this method enhances the immune response in a felid compared to a method in which a naked DNA vaccine is administered to a felid. Also provided is a method to deliver a nucleic acid to a felid. This method comprises parenterally administering to the felid a composition that includes a nucleic acid molecule complexed with a cationic lipid.