A US teenager has been arrested after he was caught on video having sex with a horse in a barn.

The owners of the barn in Corvallis, Oregon, had installed the video surveillance camera after previous assaults on the horse, reports the Corvallis Gazette-Times. They were shocked to see footage of the teen sexually assaulting the mare when they checked the video in February.

Deputy Clay Stephens, who viewed the video, said the youth seemed very practiced, not hurried but not wasting any time. He seemed to be following a "very concise, deliberate, well-thought-out plan".The owners then installed a silent alarm in the barn which sounded in their house at about 2.30am on June 7.

They checked the video monitor, saw the teenager preparing to assault the horse again, and called the sheriff's office.Police officers rushed to the scene and arrested the teenager who was charged with burglary and sexual abuse of an animal.