Jonathan "Jon" Tilley
1934 - 2025
It is with profound sadness that we announce the passing of Jonathan "Jon" Tilley (Thomson 1951), who died peacefully on Friday, 2 May, at the age of 90, surrounded by his loving family. Jon lived an extraordinary life marked by innovation, friendship, and a remarkable ability to see the best in everyone he met.
Born in Durban in 1934, Jon attended King Edward Preparatory School before joining St John's College, where he entered in Remove. At St John's, he became known for his soapbox carts and was the first and only student to drive one down the steep slope of Munro Drive, though the cart's back tyres didn't survive the adventure.
Jon went on to graduate from the University of Natal with a degree in Agriculture, where his adventurous spirit showed early when he became the first person to drive a two-wheel-drive vehicle up the Sani Pass without outside help. His academic achievements included a cum laude thesis that contributed to the first successful intercontinental embryo transfer, resulting in two lambs named Romulus and Remus born at Ukulinga Research Farm in 1960.
His professional career began at AECI, where he developed the world's first urea block, a simple but revolutionary solution for slow-release protein supplementation in ruminants. This innovation put him in contact with scientists worldwide. Jon's work on oestrogen in fertilised grass could have earned him a doctorate, but the research was purchased by a Swiss company developing alternatives to the birth control pill.
Jon was a pioneer in the South African agricultural sector. He established the Clewer Hereford Stud at Jim Bailey's Monaghan Farm, challenging and eventually changing regulations by using artificial insemination in pedigree beef herds. His work with embryo transfers achieved an 82% calving success rate, a world record at the time, leading to his invitation to the World Conference on embryo transfer in Denver, Colorado.
A founding member of the South African Society for Animal Production, Jon was recognised as a Professional Animal Scientist (Pr Sci Nat), despite having only a BSc degree, a testament to his practical contributions to the field. His articles on acid binding capacity of weaner feeds, negative electrolyte diets for lactating sows, and the use of organic chromium in grower diets were published in "Porcus" and "Pig International."
The St John's College community remained central to Jon's life through decades of friendship with his fellow Old Johannians. His son's dyslexia brought him into professional contact with Walter Macfarlane (Alston 1950), who had been at school with Jon and later became the Headmaster of St John's. Walter, who married the daughter of Jon's housemaster, "Boetie" de Klerk, and his wife, Kim, were regular visitors to Jon's farm, where their five children became "pig-watchers."
Jon's commitment to education also connected him to Deane Yates, the retired headmaster of St. John's College, who founded the Alexandra Education Committee. Through his friend Clare Rossouw, who managed this initiative, Jon supported this work to provide quality education to promising students from Alexandra township.
Beyond his St John's connections and professional achievements, Jon was a passionate motorsport enthusiast. From his early soapbox days at the College to sponsoring the "Pork Racing Team” that won South African championships in both open and 350cc classes in 1977, his love for racing connected him with world champions like John Surtees, James Hunt, and South Africa's own Jody Scheckter.
Jon's life was enriched by his three children: John, a medical intensivist who was Head Boy of Redhill and a top-performing matriculant; Este, who showed leadership from her first month in grade one and went on to excel academically and professionally; and David, who overcame dyslexia to become a successful consulting engineer in Louisiana.
After the end of his first marriage, Jon found love again with Susie Pullen, a widow with two young children. Their 37-year marriage was a testament to their deep connection and mutual respect. Together they travelled to 73 cities and towns from Hong Kong to San Francisco, crossing the English Channel by jetboat, hovercraft, ferry, and "chunnel train."
Although ill health prevented him from visiting St John's in his final years, Jon remained a passionate Old Johannian throughout his life. He maintained strong connections with various members of staff and continued his legacy of service through the anonymous sponsorship of awards at the school.
Throughout his life, Jon maintained that the secret to his enjoyment of old age was "having a wide variety of friends and acquaintances who are prepared to share their ideas, thoughts, plans, problems, privileges, and successes." He believed that "the establishment of a wide variety of friends and contacts is a spinoff of seizing a wide variety of opportunities which seemed to spontaneously occur throughout my life."
Jon is survived by his wife Susie, his children John, Este, and her husband Harry, David, his wife Donna, and his grandson Luke.