A veterinarian pleaded guilty to falsifying records in a case that included the arrests of four people in an alleged plot to fix harness races by injecting horses with banned performance-enhancing drugs.

John Witmer, 68, of Freehold, N.J., pleaded guilty yesterday before Superior Court Judge Bette E. Uhrmacher to fourth-degree falsifying or tampering with records, the state Attorney General’s Office said.

Witmer admitted he included charges on bills for one prescription medicine while actually providing another one to Seldon Ledford, the owner of Ledford Stables, according to authorities.

In a plea bargain agreement, Seldon Ledford, 60, pleaded guilty last week to third-degree conspiracy to possess an anabolic steroid. His son, harness-racing driver Eric Ledford, 35, and two stable employees pleaded guilty to third-degree possession of a controlled dangerous substance.

The New Jersey Racing Commission last year suspended both Ledfords for more than 10 years and fined them $10,000 each. Eric Ledford, who has 3,733 wins and purse earnings of $42.2 million, is seeking reinstatement.