Other government departments (OGD) are all government agencies that regulate imports and exports into Canada in conjunction with Canada Border Services Agency (CBSA).
A full list of Other Government Departments & Agencies can be found here.
In order for CBSA to process a customs release on regulated commodities, they must be reviewed by the appropriate department first.
Examples of these departments are the Canadian Food Inspection Agency (CFIA), Natural Resource Canada (NRCan), Health Canada, and Trans Canada which regulate items such as food products, plants, appliances, vehicles, health products, prescription drugs, cosmetics, and chemicals.* In these cases, your declaration will require specific information regarding the commodity in order to satisfy both the OGD and CBSA requirements.
Regardless if an import has been approved through the OGD, CBSA still holds the right of the ultimate decision on whether or not a release will be granted.
When your Customs Broker asks for highly detailed information, they are doing so to ensure the commodities that you are importing are entered into Canada in compliance with all Government Departments and Canadian Acts and Regulations.
*This list of OGD and regulated commodities is an example and is not to be considered all inclusive.