Graduated in Veterinary Medicine in 1996 from the University of Córdoba. He completed his university studies with a dissertation entitled “Passage and the Effects of Collection in the Purebred Spanish Horse.”

He completed an internship at the Klinik für Pferde of the Tierärztliche Hochschule Hannover (Germany).

In 1997, he served as a military veterinarian at the Military Stud Farm (Yeguada Militar) in Jerez de la Frontera, where he was closely involved in stallion selection programs and the maternal genetic lines of the stud. At the end of 1997, he joined Dr.Leon Lizaur’s team as an assistant veterinarian on the Costa del Sol. In 2001, he traveled to California, USA, to continue his training in various fields at the prestigious San Luis Rey Equine Hospital, working alongside world-renowned professionals such as Dr. Norman Rantanen and Dr. Natasha Werpy in diagnostic imaging, and in sports medicine, neurology, and orthopedic surgery with Drs. Barrie Grant, Joe Cannon, and Mark Martinelli. Upon returning to Spain, he began collaborating with the Spanish branch of The Donkey Sanctuary. After more than two decades, he continues as the veterinarian for El Refugio del Burrito, receiving ongoing training at the organization’s headquarters in Devon, UK. He currently teaches courses for other veterinarians, organized by universities and official veterinary colleges, on donkey and mule medicine and surgery.

In 2006, together with his mentor and chief, Leon Lizaur, he co-founded the VETEQUIN group.

Today, Guillermo continues to follow his passion and lifelong dedication to horses, just as he did as a student—grateful to his teachers for showing him the path he still walks and learns from every day.