Disgraced boxing champion Glenn Foot's horse was found so neglected it had developed maggot-infested open wounds.
The stallion - named Raspy - was tethered so tightly by the Sunderland sportsman that the rope ripped its flesh.
Rather than seek treatment, Foot neglected the animal further, allowing flies to lay eggs and maggots to infest the "slice".
The 31-year-old, a former Commonwealth champion, was warned he could be jailed for the unnecessary suffering.
South Tyneside Magistrates' Court heard the stallion was found with "dreadful wounds" last August 29 in Sunderland's Wembley Road after concerned residents reported it to the RSPCA.
Insp Proctor called a vet who discovered Raspy was wearing two head collars which were embedded into his skin.
When RSPCA officers confronted Foot and asked his name, the boxer - who has a conviction for ABH - said: "What has it got to do with you?"
But with police and animal welfare officers at the scene, Foot put his 12-year-old nephew on the horse's back and sprinted away with them both.
Northumbria Police appealed for the horse and Foot was eventually interviewed.
But the former prizefighter winner maintains to deny being at fault, claiming the wounds were caused by Alsatian dogs.
Foot claimed he had checked on the horse a day earlier and it had been fine.
But prosecutor Stewart Haywood revealed an expert had found the boxer's explanation was "not credible", adding the maggots alone had been there for days.
Now Foot, who last boxed for the British title in October in Newcastle, has been warned he faces not only prison, but a ban from keeping animals.
In his absence earlier this month, a district judge found Foot guilty of causing unnecessary suffering to a protected animal, failing to ensure the animal's welfare and obstructing a person exercising power relating to an animal in distress.
That was after Foot failed to attend court. His solicitor didn't mitigate at the hearing, but pleaded for magistrates to reopen the case, claiming busy Foot got his dates "mixed up".
But the bench declined - and ordered an all options probation report ahead of the Marley Crescent fighter's sentencing on February 27.
He was told he may appeal the convictions at crown court.