It happened around 4:20 Tuesday afternoon on Route 540 and Haines Neck Road.
New Jersey State Police say the truck overturned, spilling some of the cattle on to the roadway.
An adult and two children - all inside the mini-van - were hospitalized for treatment. No word on their conditions.
The condition of the tractor-trailer driver is also unknown.
Salem County Animal Hospital responded to the scene to assist with the livestock.
