Minerva said in a securities filing that a ship transporting its cattle had tipped over after departing from the Vila do Conde port in Barcarena. There were no human victims, it said.
Local news site G1 showed images of some cattle escaping from the side of the ship and swimming at the water's surface while most remained trapped.
Williams Shipping Agents said the ship was carrying 5,000 cows, though a Minerva representative could not confirm the numbe