A Ramsey County sheriff’s deputy accused of beating his police dog pleaded guilty Tuesday to animal cruelty in Carlton County District Court.

Brett A. Berry, 48, was charged in June with assaulting his K-9 partner, Boone.

They were both attending K-9 certification trials in ­Carlton County when Berry was caught on surveillance cameras mistreating the dog.

Berry, a 15-year veteran with the Ramsey County Sheriff’s Office, was placed on administrative leave, then assigned to the detention division. His K-9 partner was placed under the care of others.

A second charge of assaulting a public safety dog will be dropped as part of his plea agreement.

Sgt. John Eastham, a spokesman for the Ramsey County Sheriff’s Office, said the ­internal investigation is not complete.

According to the Carlton County Sheriff’s Office, deputies were called to the Black Bear Casino by security officers, who said they had video evidence of animal cruelty by a hotel guest. The video showed Berry scolding the dog in the casino parking lot and becoming upset.

Video “then shows the individual pick up his dog by the collar and throw it to the ground,” according to the Carlton County Sheriff’s Office. That’s when the dog bolted from Berry and tried to run back into the casino. The dog made it only past the first set of doors, however, and became trapped in the vestibule.

Berry allegedly caught up to the dog and struck it several times.

Berry was not arrested. He was charged with two misdemeanors after the security video was turned over to the Carlton County attorney’s office.

In a statement following the incident, the Ramsey County Sheriff’s Office said that when it learned of the incident, it “took quick, decisive action.” Berry was sent home from the trials and placed on administrative leave. His K-9 partner was evaluated by a veterinarian and no injuries were found.

Berry’s sentencing is scheduled for Feb. 17.