Police are continuing to investigate after reports that a cow was seen in the back of a car on the M4 near Briton Ferry last month.
Officers have now spoken to the driver and inquiries are ongoing.
South Wales Police said detectives are investigating to see if any road traffic or animal welfare offences had occurred, but added that it would not comment further on the investigation.
Pictures of the car were shared widely on social media and the RSPCA animal charity expressed concern.
“Unacceptable”
An RSPCA spokeswoman said: “This is a completely unacceptable way to transport a large, farm animal.
“This represents an animal welfare concern but also a risk to the safety of the driver and other road users.
“We would strongly urge people never to transport an animal like this.”
Penalties for overloading a car include fines of up to £300 as well as three penalty points.
