First off, let's get the terms correct. I am assuming that you are rendering out a movie as opposed to exporting a timeline, which is done via the File menu.
Secondly, you are referring to field ordering and not field dominance. They refer to entirely different issues. In AE, field rendering for rendered movie is set in the Render Settings dialog. For progressive output, ensure that the Field Render option is set to Off.
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You should also check that AE isn't separating fields in the Interpret Footage settings. All but the most expensive cameras shoot Progressive Segmented Frame, which AE can interpret as Upper Field First. It should be set to None.
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