A dead steer was found at a fraternity house near Oklahoma State University's campus on Friday, around 24 hours before the Cowboys and Texas Longhorns face off in the Big 12 championship football game ... and now, police are investigating.

According to J.D. Miles of CBS 11, the carcass was discovered around 6:30 AM in front of the FarmHouse Fraternity ... with its stomach cut open. The words "F*** FH" were also written on the longhorn's side.

Authorities have since removed the animal from the property ... and while a motive hasn't been officially given, most believe the act is tied to OSU's huge Saturday game against UT -- whose mascot is a longhorn.

"Oklahoma State University is appalled at the disturbing display of animal cruelty that occurred overnight at an off-campus location near a fraternity house," OSU officials said in a statement following the animal's discovery.

"The Stillwater Police Department is investigating the incident, and the university’s Office of Student Support and Conduct also has initiated an investigation."

"Oklahoma State expects all students to adhere to university codes of conduct, and appropriate action will be taken based on the outcome of the investigation."

Police are asking anyone with information to call 405-372-4171 or the tip line at 405-533-8477.

The OSU vs. UT game, meanwhile, will kick off at 9 AM PT at AT&T Stadium in Arlington, Texas.