A dual carriageway was closed during the rush hour after several cows strayed onto the road and were hit by vehicles.
Essex Police said on Twitter that people in the vehicles suffered “some minor injuries” on the A12 Witham bypass on Friday morning.
The force said it is believed that nine cows died in the incident.
Officers were called just after 3am on Friday and the dual carriageway fully re-opened just before 9am.
Police said two people were treated by ambulance staff for minor injuries and one person was taken to hospital.