David Blair Coates: a career of contribution to the northern Australian cattle industry

Introduction

David was born on the 14 November 1941 in Brisbane to John Edward Coates and Noemi Victoria Coates (Joyce) and passed away in Brisbane on the 24 January 2024. His family had deep connections into the Queensland pastoral industries with cattle stations in the Cracow and Eidsvold areas of south east Queensland. His family was affected by WW2 with his father and uncles in the military, and his father killed serving in the RAF in the famous Dambusters Squadron. During the war years, his mother managed Gyranda station. David grew up in Brisbane, but most school holidays were spent on cattle properties with cousins and friends where he developed a love of the bush. He excelled academically during both primary and secondary schools and was an accomplished gymnast. As one of the top 25 students in the Senior Public examination of his year in Queensland, he was awarded an Open Scholarship for university. David studied at the University of New England and graduated in 1963 with First Class Honours in Rural Science and a University Medal (Fig. 1). He returned to the bush working on Camboon cattle station near Theodore, gaining extensive hands-on experience in the beef industry.

Fig. 1.

David Coates in his undergraduate years.

Early career

In 1966 he was appointed as the first Officer-in-Charge (OIC) of the CSIRO Narayen Research Station, Mundubbera. Narayan was an undeveloped 11,000 ha block separated off from Hawkwood station, and the primary responsibility of the OIC was to develop it as a research station to service the grazing cattle industries in the subtropics. Living conditions at Narayan were initially basic. Early priorities were to construct housing, sheds and infrastructure, fencing, a stockwater system, to establish improved pastures and a cattle herd, and to initiate plot and grazing research trials. The herd was based on Herefords and Belmont Reds with strict selection for fertility, growth rate and tick resistance. David was the President of the Africander-Belmont Red breed Society from 1975 to 1977.

In 1979, David was appointed OIC at the Kimberley Research Station, Kununurra, that focused on R&D for irrigated cropping (rice, sorghum, soyabeans and kenaf) in the Ord River Irrigation Area. Cotton that had been the principal crop had to be abandoned because of uncontrollable insect problems, and there was a great need for alternative crops. Around his management role David found some time for direct involvement in research. An achievement with a colleague was to crack the then 10 tonne/ha yield barrier for grain sorghum in Australia. Life in Kununurra provided an opportunity for magnificent fishing with a good haul on most occasions and a 37 pound barramundi to add to bragging rights.

Contribution to phosphorus nutrition research

In 1982, David transferred to the CSIRO Davies Laboratory in Townsville, to work as a research scientist in rangeland cattle production. His early work, as part of a large team, was to address the widespread problems of phosphorus-deficient soils and associated phosphorus deficiency in grazing cattle in many northern Australian rangeland systems. At that time it was known that phosphorus deficiency was a major problem for productivity of grazing cattle in the extensive rangelands of northern Australia, but there was little understanding of phosphorus in either the pastures or the cattle. David’s work was in the phosphorus nutrition of both pastures and cattle with colleagues in CSIRO, Queensland DPI and University of Queensland, and gave rise to some 28 papers. David was one of the authors of many in a series of 11 review papers in the Tropical Grasslands journal reporting this body of research (Coates et al. 1990; Kerridge 1990). This was internationally ground-breaking research on grass and grass–legume pastures growing on very low phosphorus soils, and of the associated cattle production. It developed understanding of the expected responses of grass and grass–legume pastures to phosphorus as a fertiliser and of cattle to phosphorus supplementation (Coates 1994, 1995). David continued research on phosphorus in grazing cattle with colleagues from the Queensland Department of Primary Industries, James Cook University and the University of Queensland. This included the role of phosphorus on breeder-cow fertility and developing an understanding of the role of bone mineral reserves through extended phosphorus deficiencies (Coates and Ternouth 1992; Coates et al. 2018, 2019). David had an integral role in research over three decades on the role of phosphorus in grazing cattle in the tropical rangelands that developed an understanding unequalled around the world. It provided the knowledge to rewrite recommendations for the management of the phosphorus nutrition of grazing beef cattle that is important for cattle management in Australia and elsewhere, particularly in South America and Africa.

Development of faecal NIRS in Australia

In 1992, David set out to develop for northern Australia a novel approach to measure the quality of the diet selected by grazing cattle. Research in North America (Brooks et al. 1984; Coleman et al. 1989; Stuth et al. 1989; Coleman 2010) demonstrated that near-infrared spectroscopy measurements of faeces of ruminants (faecal NIRS or F.NIRS) could be used to measure the quality of the diet selected by grazing cattle. NIRS was a well established technology to measure the composition and nutritional quality of forages, grains and foods. The insight was that even after digestion of forages there was sufficient information in the NIR spectra of cattle faeces to measure the protein and digestible energy of forage diets with acceptable accuracy and reliability. David initiated and led a major collaborative program that developed F.NIRS for subtropical and tropical pastures in northern Australia. This involved collaboration with Dr Jerry Stuth from Texas A&M University, and with numerous colleagues and producers across northern Australia (Coates 2004; Dixon and Coates 2009; Coates and Dixon 2010, 2011). It also extended the technology to measure additional aspects of cattle diets, including, importantly, the proportions of grasses to dicotyledonous plants (legumes, forbs and browses). These are important to the nutrition of cattle grazing tropical rangelands (Coates and Dixon 2007, 2008a).

F.NIRS measures dung pats to provide rapid, economical and reliable measurements of the quality of the diet of grazing cattle, and also of other herbivores, and allows ready application of nutritional sciences for research and for management of cattle grazing extensive rangelands. Important practical applications in the cattle industry follow from the capacity of F.NIRS to provide objective information for the nutritional management of cattle grazing tropical grass pastures. Examples include ready measures of when grazing cattle become protein deficient and will respond to protein (urea) supplements, and to support diagnosis of phosphorus deficiencies (Coates and Dixon 2008b). In the past, the estimation of the diet of cattle grazing tropical pastures, especially in extensive rangelands, involved guesswork rather than science.

There were many challenges, and much scepticism and disbelief from colleagues, that F.NIRS could be developed as a reliable and routine measurement of the quality of the diet selected by grazing cattle. However, through good science, meticulous laboratory procedures, hard work and persistence, David was able to establish the validity of F.NIRS for cattle grazing major northern Australian pasture systems. One of his challenges was to obtain the support to purchase a costly NIRS spectrometer. David is remembered by some of his NIRS colleagues for visiting them with a suitcase of faecal samples ready to scan on their instrument. With David’s leadership, there was wide support from cattle producers, beef extension officers and scientists across northern Australia. This led to securing the necessary funding and extensive collaboration with the Queensland, Northern Territory and Western Australian Departments of Primary Industries and the University of Queensland. The outcome some three decades later has been unequivocal acceptance of F.NIRS as an essential tool for research involving the nutrition of grazing cattle, and an important tool to guide commercial management of cattle. The role of F.NIRS to provide reliable measurements of the diet of cattle grazing northern Australian pastures has been established in many publications.

David’s legacy

David invested much time and effort to inform others in research and extension, graziers, and the cattle industry, about the research and its application, and always with consideration of which new knowledge would be of most practical importance in commercial management of grazing cattle. He was a frequent participant at conferences, meetings and field days, always with a strong story and always generous with his time to assist producers and colleagues (Fig. 2). His work is reflected in numerous scientific publications and reports that demonstrate his commitment to both good science and the improvement of the beef industry through the application of science. He was an author on some 90 published papers and of three book chapters. David’s dedication to science was such that he continued working in his laboratory on a voluntary basis for a number of years after formal retirement to progress the application of faecal NIRS technologies. His reviews of manuscripts for journal editors were always rigorous and he would take time to assist authors who were inexperienced or had challenges with English as a second language. Furthermore, he considered that identifying himself to the authors was part of his responsibility as a reviewer. For his contributions, he was honoured in 2008 by being made a Fellow of the Australian Society of Animal Production (now the Australian Association of Animal Sciences). David was a scientist who was prepared to give forthright opinions on the direction and management of R&D for agriculture such as the importance of meticulous work, considered thought, and the need for focus on quality rather than quantity in publications. These opinions did not always improve his popularity with managers in the modern era.

Fig. 2.

David Coates, a highly respected agricultural scientist who spent a lifetime working for the northern Australian cattle industries.

David was committed to his family. He and his wife Clare met when they were undergraduates at UNE and married in 1968. One of his little-known accomplishments, at least to his colleagues, was that he was a self-taught guitar player and was blessed with a good voice for the entertainment of his family. In 2011, David and Clare relocated from Townsville to Brisbane to be nearer to their two sons Tim and Michael and their wives Anne and Leah, and to their grandchildren. He was a tireless worker over many decades in his Church and in numerous community activities such as charities, support organisations and junior sport. Unfortunately, in late years David had Parkinson’s disease with its associated difficulties.

David Coates will be remembered for his outstanding contributions as a ‘quiet achiever’ in his professional career, and in particular for developing F.NIRS of dung as a management tool for the northern cattle industries. He had the hallmarks of a traditional outback Queenslander, including physical stamina, good humour, kindness, no tolerance of nonsense, and an unashamed Christian faith.