Denielle Gallagher: Making Horse Health & Happiness the Keys to Elite Performance

Upper-level dressage rider Denielle Gallagher-Legriffon has built her career through years of dedication, hard work, and international experience. Her journey has led to an impressive résumé, including Nations Cup team appearances, multiple Olympic shortlist selections, and Grand Prix wins at the three- and four-star level.

Along the way, she has always made a point of giving back to the sport. She was named Volunteer of the Year by Equestrian Canada after working at the North American Youth Championships, where she served as Chef d’Équipe for the Young Riders, Juniors, and U25 teams.

Beyond her accolades, it’s Denielle’s day-to-day commitment to the horse that truly defines her program and career. Every decision comes back to her main goals: keeping her horses healthy, happy, and performing at their best. Her horse-first approach continues to shape both Denielle’s success in the ring and the longevity of the horses she develops.

An Early Start for a Well-Rounded Rider

Raised in Brampton, Ontario, Canada, Denielle Gallagher-Legriffon was surrounded by a family deeply rooted in equestrian sport. Her father competed in eventing and her mother in dressage. Together, they built a life centered around horses, competition, and running their own hunt club.

“My parents and I moved to New Brunswick when I was a couple of years old to build a barn and start their business,” she says. That business, Galloway Ridge Training Center, became the foundation of Denielle’s riding career.

Eventually, Denielle left home to pursue top-level show jumping competition experiences in Ontario, opening her eyes to the next level of competition.

“I decided to spread my wings and groom for Eric Lamaze, working alongside riders like Juergen Von Butler and Martina Pracht,” she says. “I spent a couple of years grooming, traveling, and experiencing FEI competition at an international level.”

From Jumping to Dressage: A Career-Defining Change

The next pivotal shift in Denielle’s career came when she began working for Olympic dressage rider Ashley Holzer. This experience not only redirected her focus as a rider but ultimately shaped both her professional path and personal life.

Her up-close look at elite dressage inspired deep consideration for the skill required, giving her an entirely new appreciation for the sport. Eventually, her time with Holzer led to a defining milestone: her first true dressage horse and her entry into Grand Prix competition.

“Ashley was always great about having her working students ride together in group lessons every day, so we could watch each other and learn,” she says. “That environment was really special. At one point, all the clients came together and surprised me by buying me my very first Grand Prix horse as a gift.”

Her new Grand Prix horse was Abrikos, a black Russian stallion purchased from Tina Konyot. Abrikos helped launch Denielle’s career as she started her Grand Prix journey. Her progression in the world of upper-level dressage also led to a more personal development—meeting her future husband.

“I met my husband, Bertrand LeGriffon, when I was in Calgary at Spruce Meadows,” she says. “We had a long-distance relationship for many years because I was traveling all over the world, and he was as well. Eventually, we got married and had two daughters, and they’re both riding and loving it.”

Over the years, Denielle has built an impressive international dressage résumé, including representing her country on two Nations Cup teams and earning multiple selections to the Olympic shortlist. She was shortlisted with Abrakos for the Beijing Olympics and shortlisted again with Argo Conti, an Oldenburg stallion, for the Pan Am teams.

Denielle had several Grand Prix wins with a Lusitano gelding, Come Back de Massa, including three- and four-star wins in Ocala. She was eventually shortlisted for the Paris Olympics with Come Back as well.

A Champion for Horse Health & Happiness

Denielle centers her business around developing her own horses and those she rides for clients. The core of her program is a philosophy grounded in the horse’s welfare, happiness, and long-term development.

“For me, it’s about setting goals and working toward them every day, but also being willing to adjust if something doesn’t feel right. If it starts to feel like too much pressure, I’ll step back and change the approach or try something different based on what the horse needs.”

 

Denielle bonds with every horse she rides, knowing and respecting that they each have individual needs. She’s committed to providing each horse the best experience possible while they’re in her care.

Prioritizing Natural Nutrition in High-Performance

Strategic nutrition is a cornerstone of Denielle’s program, as it is essential for supporting peak performance at the highest levels. “If they’re not healthy on the inside, they can’t do their job,” she says. “It’s no different than us. Horses need to be healthy and eat well to perform.”

A natural, minimally processed diet is a central part of her overall nutrition strategy for optimum performance. Her nutrition program aims to mimic what the horse would have in a more natural environment, while also providing enough nutrition to support her horses through high training demands.

 

 

 

With this in mind, her decision to incorporate Mad Barn into her program came from a combination of curiosity, research, and firsthand experience.

“I reached out to Jess at Mad Barn. She came out to my barn, did a full evaluation of my horses, and even reviewed my hay, which is something I had never had a feed or supplement company do before. That made a huge impression on me. It felt like they genuinely wanted to help. I started with a few products, and Come Back did really well on them. Then I gradually transitioned more horses over, and now all of my horses are on Mad Barn.”

Denielle was most impressed by the quality of the ingredients, price point, and the hands-on diet evaluation that Mad Barn provides. When she was preparing to compete in Europe her confidence in Mad Barn was solidified.

“I asked how I could manage feeding Mad Barn products overseas, and they arranged to ship everything—three months’ worth of supplements for five horses—free shipping directly to France. That level of support meant my horses didn’t have to change anything, even while traveling and competing internationally. It made me feel like they truly stand behind their products and the riders they work with, even before I was officially sponsored.”

Denielle uses a core group of supplements to support overall health, recovery, and performance. Every horse in her barn receives MSM and vitamin E, as she finds many performance horses tend to be deficient.

“Electrolytes are another staple,” she says. “Especially since my horses are all in work and competing regularly. I also include Visceral+ for gastric support, and AminoTrace+ for a balanced vitamin and mineral base.”

From there, Denielle layers in additional supplemental support based on each horse’s individual needs. Come Back’s response to Spirulina, however, led Denielle to expand its use across her entire program.

“I’ve started putting more of the horses on Spirulina as well since it worked well for Come Back,” she says. “Overall, most of my horses are on very similar programs. That’s one of the things I really like about Mad Barn, the products work well across a wide range of horses.”

Lusitano Horses: Breed-Specific Nutrition for Metabolic Health, Hoof Health, & Performance

As Denielle learned through her time with Come Back, Lusitano horses can be sensitive and energetic in nature, which requires a unique approach to training and feed management.

“Lusitanos are sensitive horses, so they need a lighter, more thoughtful approach in both training and nutrition,” Denielle explains. “You have to be careful not to overstimulate them or use high-sugar feeds or supplements. That’s one of the things I like about Mad Barn, it keeps things simple without all the extras.”

With numerous Lusitanos horses in her program, Denielle tailors her nutrition strategy to the breed’s unique needs, carefully managing body condition and metabolic health.

“Lusitanos can become metabolic pretty easily,” she says. “That’s always been a concern for me, especially with how high in sugars and starches many feeds and supplements are. A lot of products out there have a ton of fillers or ingredients that can contribute to issues like metabolic conditions.”

For a while, Denielle fed a rich timothy hay to support her horses’ forage needs, but she noticed they started gaining weight on it. When she traveled to Europe, their diets changed to basic grass hay and they leaned out. After coming home, she worked with Mad Barn to evaluate and balance her overall feeding program and saw a significant improvement in her horses’ condition.

Denielle also saw significant improvements in hoof quality, an area she pays close attention to with Lusitanos.

“With Lusitanos, you often see smaller, weaker feet, but that’s not the case with mine anymore. My Lusitanos’ feet look amazing, and I credit that to balanced nutrition, especially through AminoTrace+. It supports things like hoof growth and overall quality, and you can really see the difference,” she says.

Come Back de Massa: Keeping Up With Demands of High Performance

Because many of her top horses are owned by clients, long-term competition partnerships are rare for Denielle, making her bond with Come Back de Massa especially meaningful.

“A close friend of mine, Ellen Lazarus, bought Come Back and has always said we’re in this for the long haul,” she says. “As long as he’s happy, sound, and still wants to do the job, there’s no pressure to sell him. That’s been pretty amazing, because it’s the first time I’ve really been able to build that kind of long-term partnership in upper-level dressage.”

 

Denielle makes sure Come Back has the nutritional support he needs to keep performing at high levels. Since switching Come Back to Mad Barn products, she has seen a noticeable improvement in his condition.

“He’s never looked better since I switched him to Mad Barn about a year ago,” she says. “I was just looking at pictures of him in Wellington during the Nations Cup, and he’s so shiny, his muscles are really standing out.”

Targeted nutritional adjustments have also made a measurable difference for Come Back during periods of stress and travel. After returning from Europe, Come Back lost some weight and topline from the stress of travel and competing.

Over the next couple of months, Come Back also completely rebuilt his topline. “When Jess saw him again, she couldn’t believe how much he had changed. Nothing else in his program had shifted, so I really credit that improvement to the oil.”

Jeroboam de Massa and Led Zeppelin: Improved Condition & Rideability Through Nutrition

Denielle has seen similar positive changes across other horses in her program, with targeted nutrition supporting both body condition and rideability. Another Lusitano she manages for Lazarus, Jeroboam de Massa, was always a heavier type of horse and struggled with his weight.

 

“Since putting him on the Mad Barn supplements, his body has completely changed,” she says. “He no longer has that bloated look, and his muscle definition is so much better. Using AminoTrace+ has allowed me meet his nutritional needs without overloading him with sugar or excess calories.”

Led Zeppelin, a Lusitano cross in Denielle’s program, owned by Ken Marlin and Jacqueline Barnathan, has a hotter and more sensitive personality than her other horses. Since starting Mad Barn’s MSM as part of his broader supplement program, Denielle has noticed a positive change in how he feels and responds. “He just feels lighter, more relaxed, and actually less spooky,” she says.

 

A Partnership Built on Trust, Support, & Results

For Denielle, working with Mad Barn goes beyond products. What initially drew her in was the sense that the team genuinely cared and took a hands-on approach. She valued being able to reach out with questions and receive practical, personalized advice not just about supplements, but about hay, feeding, and overall management.

Denielle’s results in the ring speak to the effectiveness of her program, but it’s her consistent focus on the horse that sets her apart. By prioritizing health, thoughtful nutrition, and individualized care, she has built a system that supports both peak performance and long-term soundness. That balance continues to guide her work, shaping not only the success of her horses today but their ability to thrive well into the future.

Summary

Denielle Gallagher-Legriffon is an upper-level dressage rider whose career is defined by international success and a horse-first philosophy that prioritizes health, longevity, and performance.

• Her career includes Nations Cup team appearances, Olympic shortlist selections, and Grand Prix wins at the three- and four-star level, reflecting years of international experience
• She developed a horse-first training philosophy that emphasizes welfare, adaptability, and long-term soundness in every decision she makes
• Her transition from show jumping to dressage was shaped by hands-on experience working with Olympic rider Ashley Holzer, where she developed a deep appreciation for the discipline
• Nutrition plays a central role in her program, with a focus on forage-based, low-sugar diets that support both performance and metabolic health
• She uses targeted supplementation to improve condition, recovery, hoof quality, and topline development across her horses
• Her feeding programs are tailored to individual needs, particularly for Lusitano horses, which require careful management to avoid metabolic issues