Two years and a lot of hard work later, he made a breakthrough in his field by producing the world's first test-tube piglet.
民國七十年，農委會選送他到英國劍橋大學，進修豬的胚胎冷凍移植技術，「耐心」加上「努力」，二年後，鄭登貴培育出世界上第一隻試管豬，是改良豬種技術的一個突破。