VetScript Editor?s pick ? July 2018

After more than 52 years of research, mentorship and leadership in the fields of animal welfare science and physiology, David Mellor will retire in July. He speaks to one of his former students, Mirjam Guesgen, about his life?s work.

When David Mellor, the man behind the influential Five Domains Model and a champion of animal welfare in New Zealand, reflects on his career, he says there?s a right time for everything: a time for growing and developing; a time for extending ideas and drawing people together; and a time to step back and ?let others get on with the game?, as he puts it.

Each of the chapters of his life, and the professional achievements that came with them, were inspired and shaped by the forces, places and ways of thinking David experienced. From the boy who read widely about world religions, to the man who published on everything from the onset of consciousness to equine welfare during exercise, he has had a knack for drawing seemingly disparate ideas together and figuring out how they may relate as an integrated whole.

As his academic career draws to a close and the post-retirement (?realignment),? phase begins, David muses about how a wide worldview has been so integral to his success.

His introduction to animals came during a year spent on an uncle?s farm in South Australia, away from his home city of Melbourne. There, he threw himself into every farming activity imaginable, from wool classing to spotlight shooting rabbits. ?David was born to it?, he remembers his uncle telling his father.

Unlike farming, school didn?t come naturally. He confesses to struggling due to a period of illness and dyslexia, and he repeated his final year at high school so he could attend the University of New England in New South Wales.

What began as a rural science degree quickly turned into a lifetime passion for a different subject, physiology, which he was introduced to in his second year. ?It just sparked something inside me that really engaged my interest and enthusiasm,? David recalls.

His first publication, which was later distributed to all physiology departments in Australia, was a flow chart outlining the interactions between all the major organ systems of the body. It became clear that what David describes as an ?inbuilt predisposition? for integrating ideas was one of his most valuable assets, and one that would continue to play a role in his work.

So, too, was his boldness. After gaining honours at the University of New England, he travelled to Scotland to complete his PhD in foetal physiology at the Moredun Research Institute. When the director of the institute off-handedly commented that the physiology department would be dismantled because there was no physiologist to run it, David quickly replied, ?You?ve got one sitting in front of you?. That reply, backed by David?s already impressive knowledge base, turned into a head of physiology position, which he held for 18 years.

Inadvertently, David?s work at Moredun helped him to begin forming theories of animal welfare. His research investigating prenatal causes of lamb mortality aligned well with his later animal welfare interests in terms of the onset of consciousness. At the time, however, animal welfare science didn?t exist, and it certainly was not being discussed widely academically.

It was the political and social forces of the period that thrust animal welfare thinking to the forefront of David?s mind. The anti-vivisection movement of the 1960s and 1970s was strong in the UK, and protests outside the institute gates became increasingly violent.

Closer to home, David?s late first wife, Gourie Nag, a philosopher, ethicist and a woman who David describes as intellectually honest, influenced him to address the ethical justifications behind using animals in research. Together, they strived to see the world from another?s perspective, ?uncontaminated from one?s original starting point?. It was a way of thinking that persisted throughout his career.

David?s transition from physiologist to animal welfare scientist was accelerated when he came to New Zealand in 1988 to take up a position as head of the Department of Physiology and Anatomy at Massey University. He had been assessing how lambs responded physiologically and behaviourally to castration and tail docking. Within a week of those studies appearing in academic journals, David recalls, the then NZVA President Cathy Smith was standing in his office asking him if he was interested in animal welfare. That?s where it all officially started, he says.

His talent for integrative thinking once again made a strong appearance in his work. He formalised his ideas around the nutritional, environmental, health, behavioural and affective aspects of animal welfare into the Five Domains Model (Mellor and Reid, 1994). David says his experiences and research up to that point had primed him for bringing the concepts together. His work with sheep in the 1960s and ?70s made him acutely aware of how the health of an animal affected its ability to recover from surgery; the pens the sheep were kept in showed him the effects of restricting behaviour; and he never doubted for a moment that dehydrated ewes in his experiments were experiencing thirst.

While asserting that a dehydrated animal is thirsty may seem obvious now, that wasn?t the case in the early 1990s. Perhaps ironically, a non-emotional way of thinking about animal welfare was most entrenched in those who stood to gain or lose from an animal?s wellbeing ? researchers, veterinarians and farmers.

Animal science was clinging to its physically functional past. Scientists were at best trepidatious about, and at worst antagonistic towards, the idea that animals possessed emotions or motivations, let alone the idea that positive emotions could be promoted. Meanwhile, veterinarians clung to the biological function view of animal health, which was limiting because, according to that view, without physical signs of disease or injury there would be nothing wrong with an animal. Farmers saw animal welfare as a thing for overly sentimental folk, and thought it contributed nothing to the efficiency or economy of their businesses.

It took evidence and incremental change over more than a decade to get to a place where people are now trying to provide positive opportunities for animals. David was there the whole way.

The advent of affective neuroscience provided a methodology for scientists to understand and study the physical basis of subjective emotional experiences. ?Now we had an understanding of the neural pathways and the receptors involved [in animals? emotional experiences]. That took out the factor that was unsupported speculation,? says David.

Veterinarians who were highly interested in animal welfare paved the way for others to follow. Cathy Smith, who was working closely with both David and the late David Bayvel, says they inspired her and gave her the strength to push for better animal welfare understanding and legislation. Together they spoke to farmers and drew their attention to the then dominant model of animal welfare, the Five Freedoms, which demonstrated the rigour of animal welfare science. They also argued that animal welfare was needed if farmers wanted to maintain access to other markets such as Europe. Soon, even the president of Federated Farmers stood up in support.

As chair of the National Animal Welfare Advisory Committee, David and others prepared voluntary codes of welfare in consultation with farmers. The Animal Welfare Act of 1999 gave those codes greater legal bite than the previous voluntary codes had, and an amendment in 2015 meant that not meeting regulated standards could result in a fine or prosecution. Incremental change, from preventing cruelty to promoting wellbeing, was key.

The Act captured the mood of the time. It was the first of its kind in the world and demonstrated New Zealand?s leadership in animal welfare ? leadership that David believes continues to this day.

Now, the thinking has moved on, he says, and everyone is ?more up with the play?. The recognition of animal emotion as a key aspect of welfare is becoming more deeply canvassed in veterinary degrees. ?Those with a strong interest in the subject will continue to draw, not drag, the rest of the profession along with them.?

Nearly a quarter of a century since its inception, David?s Five Domains Model is now used to inform not only veterinary practice, but also scientific research, zoo and aquarium practices, and local and international governments.

It is difficult, if nigh impossible, to list all of David?s contributions and academic achievements in one article. Some of those are visible, like the New Zealand Order of Merit pin adorning his suit jacket, and his many published works lining his bookshelves. Others are less so, like the impression he left on students he mentored, and the debates that were had after his keynote addresses.

After more than 52 years of research and mentorship, David?s next career move is to step back. He will retire in mid-July ? although he doesn?t see it as a retirement, but rather a ?realignment?. He plans to pursue his other great loves: spending time with his wife Lynda and son Thomas, and enjoying non-scientific writing, poetry and golf.

When asked if he has accomplished everything that he wanted to do professionally, he replies, ?More than I could have even imagined?.


Mellor, D. Operational details of the Five Domains Model and its key applications to the assessment and management of animal welfare. Animals 7(60), 1?20, 2017

Mellor D, Reid C. Concepts of animal well-being and predicting the impact of procedures on experimental animals. In: Improving the Well-being of Animals in the Research Environment. Australian and New Zealand Council for the Care of Animals in Research and Teaching (ANZCCART). Pp. 3?18. Glen Osmond, SA, Australia, 1994