Preheat a smoker to 250°F and add hickory wood according to the smoker’s instructions. Line a small rimmed pan with foil or set out a suitable grill-safe pan for the meatloaf.
In a large bowl, combine the venison, ground pork, breadcrumbs, egg, onion, milk, Worcestershire sauce, salt, pepper, garlic powder, and 2 tablespoons of the ketchup. Mix gently with your hands just until the ingredients are evenly distributed. Avoid packing the mixture tightly.
Shape the mixture into a loaf about 8 inches long and place it in the prepared pan. Make a shallow channel along the top to help hold the glaze.
In a small bowl, stir together the remaining ketchup, brown sugar, and apple cider vinegar. Brush about half of the glaze over the meatloaf.
Place the pan in the smoker and cook until the center reaches 155°F, about 1½ to 2 hours depending on the loaf’s thickness and your smoker. Brush on the remaining glaze during the last 20 minutes of cooking.
Remove the meatloaf when its center reaches 160°F. Let it rest for 10 minutes before slicing so the juices settle and the slices hold together.