Tullis has practised Artificial Insemination (AI) in stallions and freezing semen for over 30 years. Stallion AI Services has been honoured with a prestigious Queen’s Award for Enterprise, for its excellence in Innovation. Tullis works with Chester Zoo to help cryopreserve semen from endangered species. Tullis established a charity, Nature’s SAFE, Europe’s only living Biobank, aimed at assisting in the conservation of the worlds’ most rare and endangered species.