Robert F. Kennedy Jr. could be parted from his share of a $2,500 horse named Killarney as a result of a lawsuit filed in Charlottesville by a 24-year-old woman graduate student at the University of Virginia.

Jody Ann Jacobson has won an injunction barring Kennedy, a May graduate of the university's law school, from taking their jointly owned steed from its Albemarle County home in Virginia's hunt country. She has also asked a judge to order the 5-year-old bay gelding put up for sale so she can buy out Kennedy's share.

Jacobson and Kennedy bought the horse while he was at the university and a tenant on her family's farm near Charlottesville. Kennedy rode the horse -- described as a large, even-tempered hunter -- in jumping competitions around the state and in local hunts, said Connie Dempsey, owner of Foxfield Stables where Killarney is boarded.

Kennedy, son of the late Robert F. Kennedy, married Emily Black in April and is expected to start work Monday for the Manhattan district attorney in New York City. He could not be reached for comment yesterday.

Jacobson went to the Albemarle County Circuit Court after she grew frustrated because the two were unable to negotiate a sale price for Kennedy's half of the horse, according to her attorney, Lindsay Barnes.

"It's not just the purchase; it's the care -- who rides it, how often, how it should be handled," said Barnes. "The problem is you're stuck with two people who can't agree on anything. Evidently both of them feel attached to this horse and they both want it."

The injunction was sought to prevent Kennedy from doing anything before the court rules on the case, Barnes said. "He has on one occasion said he might just come down and take the horse to New York," explained Barnes.

According to Barnes, the joint ownership began in early 1981 when Kennedy bought the horse for $2,500 at Jacobson's request. Last August, Jacobson paid Kennedy $1,250 for her half-share, he said.

"As I understand the original agreement, at the date of Kennedy's graduation, either party would have the option to buy out the other . . . but she can't get Bobby to agree on a price," said Barnes. "Even after these disputes arose, he continued to refer to the horse exclusively as his horse."

Kennedy has not filed a response to the suit.