Isabelle Costantini is quitting high performance sports with Fifth Avenue

Luxembourg Grand Prix rider Isabelle Costantini has announced that she will retire her number one, Fifth Avenue, from top-level sport.

Fifth Avenue is a 14-year-old KWPN mare by Romanov out of Rita Morka (by Jazz x Zuidhorn). She was bred by Louky Hagens-Groosman.


Originally named Famorka and coming from one of the best KWPN dam lines with Rita Morka as mother, Famorka was first released as a three-year-old by Femke de Laat and finished 6th in the VWF Dressage Cup.

In 2014 she came 7th in the VSN Trophy Final and 10th in the semi-finals of the 2014 Pavo Cup.

Before the sale, Famorka became pregnant and in 2016 produced the ET foal La Morka (by Toto Jr.), which was sold to Sweden to Elizabeth and Amanda Axtelius.

Annabelle Collins

In 2015, the mare was sold to Spain-based Bermuda dressage rider Annabelle Collins and her company Newmarket Investments. They changed its name to Fifth Avenue.

Collins competed the mare as a 6-year-old at the CDIs in Oliva Nova and Segovia before representing Spain at the 2016 World Young Horse Championships in Ermelo, where they finished 24th in the consolation final.

In 2017, her husband Agusti Elias rode the mare during CDIs in Valencia and Sant Marti Vell. They won the Spanish Young Horse Championships for 7-year-olds in 2017.

Isabelle Costantini

Agusti Elias on Fifth Avenue during Spanish 2017
Championships for young horses

Collins sold Fifth Avenue to the Luxembourg rider Isabelle Costantini, who was looking for a successor to Pari Aiko (v. Akinos x Loran). She previously represented Luxembourg at the 2013 European Championships in Herning with Rimbeau (by Royal Diamond x Westrich).

By 2016, Costantini had moved to Barcelona and is a student of Collins/Elias, who works on their farm.

The pair premiered at minor tour level at the CDI Nice in February 2019, where they achieved a triple victory. From there they went to the CDIs in Camarma de Esteruelas, Granada, Nice and Crozet.

A two-year break from international shows followed, but they returned to mid-level touring at the CDI Le Mans in October 2021, their final international.

Nationally they continued at mid and major tour levels. Their last show was at Grand Prix level on March 23, 2024.


Isabelle has announced her decision to retire the mare from top sport.

“After 6 years of competing with Fifth Avenue Bcn, after many victories in the light tour and medium tour, after a good start in the Grand Prix, I realize that my sweet mare does not feel well at competitions,” says Isabelle. “She doesn’t like to be separated from her friends. She gets very nervous in the box and screams and turns away. I have tried almost everything. I spend the whole day by her side. But most of the matches she feels feels stressed. She is actually happier when she is riding, no matter what class, than she is the rest of the day in the stable.”

For Costantini, it is a sign that her mare does not like the competition environment.

“So I have to be coherent with my slogan: respect my horse,” she said. “I have stopped doing big competitions. I might stick to some small local one-day competitions. And I will breed her. It is a very difficult decision for me. I have trained until here with all my heart, my strength and my illusion of a return to the international grand tour scene with a very talented horse, but my love for her is stronger.”

Photos ©

Related Links
Isabelle Costantini returns to the International Arena at CDI Nice 2019
Farron, Columbus TR, Santos OLD, Fifth Avenue, Euclides MOR win 2017 Spanish Young Horse Championships
KWPN foundation mare Rita Morka passed away