Thirty-five pigs have died after a container carrying 200 of the animals overturned in a collision involving a bread lorry.
Emergency services have since arrived at the scene of the crash, which took place on the A59-A1237 roundabout near York at 10.20am.
North Yorkshire Fire and Rescue service said 35 pigs were either killed or put to sleep following the incident, which involved a Warburtorns carrier and another car.
Fire crews helped move the remaining pigs to another vehicle after the incident, while two vets oversaw the animals' welfare.
No people were harmed, the service said. Police have appealed for witnesses.