There are a couple of agencies that look after our interests at the border. Of the top of my head (US and Canada):
-US Border Police/Customs and Immigration (crossborder paperwork for your person and possessions)
-BATF/CFC (for your firearms)
-Food and Drug Administration, Fish and Game Service/Health Canada, Agriculture Canada (for raw meat inspection, for animal parts and controlled species regulations)
-Michigan wildlife guys/Ontario Ministry of Natural Resources (for possession of game animals, or nongame animals as the case may be, or a hunting licence to possess firearms in the US)
-Michigan food and agriculture guys/Ontario Ministry of Agriculture (maybe one or the other worries about farm raised animals)
If it was wild game, the rules are well known. But in my mind, Russian boars or feral pigs fall in between livestock and wildlife.