Chardo said Lefever would be banned for life from obtaining a Pennsylvania thoroughbred racing license - and thus barred from any racetrack employment, such as horse training.
She also will be forbidden from acquiring any additional horses for the two-year duration of her probation, the terms of which are to be laid out at a future hearing. Lefever's next court date is an arraignment on April 19.
The defendant left with her lawyer after her brief court appearance and climbed into a pickup truck without comment.
News of the charges against Lefever, a fixture on the regional horse-show circuit and a champion rider and trainer, sent shock waves through the equine-welfare community and renewed calls, including from members of Congress, to ban the slaughter of horses in the United States and end the export of horses for slaughter.
There is no prohibition against sale of horses to slaughterhouses in Canada and Mexico, where they are butchered and sold for human consumption, primarily in France and Japan.
"This is a lawful activity," Chardo said. "The problem is if the horses were obtained under misrepresentation."
Lefever's attorney, J. Michael Sheldon, said Tuesday that "justice has been served" in what he called "an unfortunate case."
"I think it's in the best interest of justice, the commonwealth, and my client," Sheldon said. "Ms. Lefever is concerned about the safety of all horses, and this doesn't diminish her love of horses."
Prosecutors might disagree. In their written criminal complaint against her, investigators said one witness, a horse dealer, had quoted Lefever as saying: "I killed every one of those . . . horses, over 120 of them . . . Every one of them is dead. I don't even know their names and there wasn't a . . . thing [the sellers] could do about it because they gave me those horses."