Deputy Chief Constable Nev Kemp said the incident, which happened at at 00:30 BST, highlighted several issues in relation to how the police respond to loose livestock.
“We appreciate the strength of feeling which remains in relation to this incident, which is why we committed to conducting a diligent and thorough investigation to determine whether any criminal offences had taken place,” he said.
“We have already made changes to our protocol for loose livestock.”
The revised protocol includes specialist roads policing teams being deployed to support road and public safety, and that early contact is made with Surrey Fire & Rescue Service to utilise its capability and expertise.
She had been on the loose since about 21:00 the previous day, police said.
The day after the incident, Surrey Police announced the driver involved had been removed from frontline duties.
