More than 748.4 kg (1,650 pounds) of marijuana — a little over the average weight of a dairy cow — have been seized at Blue Water Bridge in Port Huron over five weeks through a series of truck inspections.

U.S. Customs and Border Protection say the first seizure was on Aug. 28, where dogs flagged multiple Canadian bulk mail packages in a shipment. A later search revealed 14 "concealed packages of marijuana" weighing more than 136 kg (300 pounds).

Customs and border officials worked with Homeland Security Investigations and the St. Clair County Sheriff's office over the following 10 days. They found an additional 63 concealed packages weighing over 589.7 kg (1,300 pounds).

The area port director says using the mail system to ship drugs is not new to the border agency. The seized marijuana will be destroyed at a later date.

All truck drivers were Canadian and released with their trucks.