UPDATE: The Warrego Hwy has re-opened after a truck rollover which led to the deaths of 24 cattle this morning.
A Queensland Fire and Emergency Services spokeswoman said the B-double truck had been loaded with 64 cattle when it rolled about 40km west of Miles about 12.55am.
A rescue mission was launched which recovered 40 of the cattle alive, while 24 were either killed in the crash or humanely destroyed by authorities.
Heavy haulage recovery vehicles righted the truck and the Warrego Hwy was re-opened to traffic about 11am.
Police are investigating the cause of the rollover.
9.40AM: Authorities are working to rescue a number of cattle injured in a B-double truck rollover west of Toowoomba this morning.
The loaded cattle truck rolled off the Warrego Hwy shortly before 1am about 40km west of Miles, killing a number of animals on impact.
While a total headcount is unclear, several cattle have been humanely destroyed on scene and others are currently being rescued from the overturned truck.
Paramedics assessed the male truck driver at the scene but he did not require transport to hospital.
Queensland Fire and Emergency Services crews are working with police to remove the dead animals from the truck to a cleared area nearby.
About eight live cattle remained on board as at 7.40am.
The eastbound lane of the Warrego Hwy is expected to remain closed until later this morning until the scene is cleared.