It happened around 10 a.m. along the westbound lanes of I-40 between S. Saunders Street and Lake Wheeler Road.
It is unclear what caused the truck hauling 2,600 piglets to overturn along the shoulder of the interstate.
Some of the animals were reportedly injured. The driver was not seriously hurt.
Two westbound lanes of I-40 were temporarily closed as crews cleared the scene.
The police report said the truck was headed west on I-40 about 10:30 a.m. when a car changed lanes in front of it, leading to a collision. According to the report, the tractor-trailer went off the interstate, across an access ramp and hit a guardrail, causing the rig to overturn.