Beating the Odds in a Big Country

The eradication of bovine brucellosis and tuberculosis in Australia

Robert Lehane

• Publisher: CSIRO PUBLISHING
• Year: 1996
• Print ISBN: 9780643058149
• eBook ISBN: 9780643102439
• Topic: Medicine
• Subtopic: Veterinary Medicine

The implementation of the Brucellosis and Tuberculosis Eradication Campaign has been one of the most significant animal health achievements in the history of Australia and worldwide. The unprecedented technical and operational complexity of the campaign presented an enormous challenge to cattle producers, veterinarians, research scientists, field staff and administrators over the 25 years of the project.

Beating the Odds in a Big Country captures the dynamism of the campaign and records the very real contribution in cash and kind made by the many producers whose herds were subject to eradication programs.

CHAPTER 1

Something to Celebrate

When some 500 cattle producers and people connected with the industry gathered for dinner at Townsville’s Sheraton Breakwater Hotel on 25 November 1992, they were celebrating a remarkable achievement. After a 22-year campaign, Australia was about to be declared ‘impending free’ of one of the worst cattle diseases, bovine tuberculosis; the declaration came on 31 December. Three-and-a-half years earlier; the nation had been declared free of another scourge of beef and dairy herds, bovine brucellosis.

The dinner provided an opportunity to reflect on the campaign’s impact on the lives and fortunes of individuals and on the industry as a whole. Something like 100 million disease tests had been conducted — a massive undertaking that made heavy demands on everybody involved, including property managers and stockmen, government and private vets, stock inspectors, laboratory workers and campaign administrators. The animals that tested positive — totalling in the hundreds of thousands — were sent for slaughter or destroyed on the spot, and in some cases whole herds or properties were ‘destocked’. Spending from campaign funds, mostly derived from an industry levy but with big government contributions as well, reached about

750 million by the end of 1992. When spending by individual producers is added — mainly on the extra mustering and property improvements needed to meet testing requirements — total costs amount to at least

1 billion.

Some producers, unable to meet campaign requirements and remain viable despite the assistance available, left the industry. For many others the outcome was more efficient and profitable enterprises based on improved management procedures and better stock. The nation, as well as producers, gained from the boost to cattle productivity that came with control of TB and brucellosis, and from removal of the human health risks posed by infected animals. And, most important of all, the campaign eliminated a major threat to beef and dairy exports — the prospect of importing nations rejecting Australian produce because of the continuing presence of the diseases.

Keys to the campaign’s success were strong industry support, the commitment of all governments — Commonwealth, State and Territory — to eradication, and the collaborative approach adopted by participants. The Townsville dinner, put on by the national BTEC (Brucellosis and Tuberculosis Eradication Campaign) Committee, reflected this collaboration; as well as producers from all over the country, guests included vets, stock inspectors, laboratory scientists and campaign administrators. They were attending various meetings in Townsville that week on cattle industry matters. One was a workshop on bovine TB called to draw together the collective wisdom of people who had been heavily involved in the TB program — for the benefit, particularly, of those handling the final stages of eradication. The BTEC Committee — the campaign’s main policy-making and coordinating body, with members from the cattle industry and all governments — was in Townsville for a regular 6-monthly meeting as well as to host the dinner.

After the meal (sirloin of beef with black peppercorn sauce), speakers from industry and government looked back over what had been achieved and a specially commissioned video, ‘The Battle for BTEC’, received its first screening. John Holmden, South Australia’s Chief Veterinary Officer, who had been involved in BTEC from the start, recited a 32-verse poem he had written — ‘The Saga of BTEC’. After telling the story of the campaign and its antecedents in rhyming couplets, he ended with this message...

I’m reminded that time’s of the essence tonight,
and so, to avoid a most terrible fight
with the Chairman, I’ll close, with one serious plea
“For continuing Freedom from B.R. and T.B.”

No-one knows just when and how bovine tuberculosis and brucellosis first found their way to Australia. Unlike diseases such as pleuropneumonia and foot-and-mouth, their impact is often insidious and they can go unrecognised in a herd for a long time. As both were widely distributed around the world, it is reasonable to assume that early cattle importations brought them here and later shipments reinforced the infection.

Australia’s first cattle — four cows and two bulls — came with Captain Arthur Phillip’s first fleet and promptly vanished into the bush south-west of Port Jackson. When rediscovered 7 years later this first herd had already grown to 61 head and, with cattle imported later, it provided meat for the early settlement. After Blaxland, Lawson and Wentworth crossed the Blue Mountains in 1813, opening up the vast pasture lands west of Sydney, cattle numbers grew at a staggering pace. By 1843, New South Wales, with a recorded population of fewer than 190 000, boasted more than one million cattle. Beef was in such plentiful supply that, weight for weight, it was cheaper in the shops than bread.

The gold rushes of the 1850s saw official estimates of Australia’s population grow from 400 000 in 1850 to 1 150 000 in 1860. In response to the rapidly expanding demand for meat, recorded cattle numbers increased in the same period from 1 860 000 to 3 958 000. Over the next two decades, following close on the heels of Stuart, Burke and Wills, Forrest and other explorers, pioneer cattlemen and their herds settled outback pasture lands in western New South Wales and Queensland, northern South Australia, and the Northern Territory and Kimberley. By 1895 cattle numbers exceeded 12 million, about half the current total, and all today’s major cattle-raising regions were occupied. The dairy industry was experiencing rapid growth boosted, like beef production, by the advent in the 1880s of refrigerated shipping to Britain. By 1900 Australia’s dairy herd numbered 1.4 million, and some 90% of the milk output went into butter and cheese production, much of it for export.

Concern about the presence of bovine TB in Australia emerged as early as 1859. Victorian authorities were notified that year of its presence in cattle killed as part of initial efforts to control pleuropneumonia, which had first entered Australia, through Melbourne, the previous year. In 1884 the Victorian Parliament appointed a Board of Inquiry to investigate ‘whether the existence of tuberculosis in cattle was likely to be detrimental to the public health and what preventive measures should be adopted’. It found the disease was widely present and recommended measures, including inspection of dairies and condemnation of cattle seen to be diseased, to reduce the risk of people contracting TB from the milk supply. The first official response to the disease in New South Wales came in 1886 with the passing of the Dairies Supervision Act, which gave an inspector the power to order the destruction of cattle diagnosed as tuberculous.

The bacterium that causes bovine TB is closely related to those responsible for human and avian TB. It is transmitted readily to humans, particularly through cow’s milk, and produces essentially the same disease as that caused by the human TB microbe. Before the widespread introduction of bacteria-killing pasteurisation from the 1930s, infection of children through milk was all too common despite the considerable efforts put into controlling the disease in dairy herds. This is reflected in 1932 figures from Melbourne Children’s Hospital where, at a time when TB was a distressingly common disease in Australia, a study found the bovine form in nearly 26% of cases examined.

Health concerns were, therefore, the main motivation behind early efforts to fight the disease. Other major incentives to action were a reduction in carcase condemnations at abattoirs and the general boost to animal productivity that comes with control of a debilitating disease. The discovery by the German scientist Robert Koch in 1890 of tuberculin, and its value in detecting TB, made an attack on the disease feasible — through a testing campaign and slaughter of any animals that gave a positive response.

Early control efforts in Australia focused on dairy cattle, and the first tuberculin tests were performed within a few years of Koch’s discovery. However, progress up to World War II was hampered by a lack of resources and generally slow. In December 1937, The Australian Veterinary Journal advised in its editorial: ‘The main thing is for our governments to press on courageously with the long-overdue task of eliminating the disease by providing the necessary funds.’

After the war, test-and-slaughter programs in all States, with compensation paid for the animals slaughtered, greatly reduced the prevalence of the disease, particularly in dairy herds. In Queensland, for example, the statistics show a decline in TB prevalence in dairy cattle from 12% in 1945, when the State’s control program began, to 0·025% in 1970. However, little attention was given to TB control in the extensive pastoral regions of the inland and north where, in some areas, high proportions of the stock carried the disease. In the Northern Territory’s Barkly Tableland, for example, up to 30% of cattle were infected in 1970. Despite the success of individual State programs, it had become clear that only a nationally coordinated campaign could eradicate bovine TB.

As a direct cause of economic loss to producers, bovine brucellosis was a more serious disease than bovine TB. However, probably because it posed very little risk to the health of the general population, control efforts were given a lower priority until threats to Australian meat exports, due to the presence of both brucellosis and TB, emerged in the 1960s. A requirement imposed (but soon lifted) by Germany that its meat imports come from herds certified as brucellosis-free dramatised the need for action.

Bovine brucellosis, earlier known as contagious abortion or Bang’s disease (after Dr Bernhard Bang, the Danish discover of the bacterium, Brucella abortus, that causes it), increases the abortion rate in cows and can lead to them becoming permanently or temporarily sterile. It also reduces milk production. People can contract brucellosis from infected animals or contaminated meat or milk, but a large dose of the Brucella organism is needed. As a result, only those in close contact with diseased cattle, notably dairy farmers, vets and meatworkers, have usually been at any risk. In the worst cases, infection produces a range of long-term, debilitating symptoms.

Tasmania was the first State to launch a control campaign, based on systematic testing of herds and the slaughter or isolation of infected animals. Steady progress through the 1930s saw Flinders Island declared free of the disease in 1938 and the north-eastern, midlands and southern regions by 1945. Continued efforts, boosted by the introduction of an effective vaccine, saw eradication finally achieved by 1973.

In the other States, little progress was made against brucellosis until the vaccine, known as ‘Strain 19’, appeared on the scene. Scientists in the United States developed this in the late 1930s from a laboratory strain of Brucella abortus that combined the vital attributes of low virulence and the power to stimulate a high degree of immunity. Production of the vaccine began in Australia, first at the Council for Scientific and Industrial Research (CSIR) and then at the Commonwealth Serum Laboratories, after the Conference of Commonwealth and State Veterinarians in 1943 adopted an Australian Veterinary Association recommendation for its widespread use.

Vaccination programs greatly reduced the prevalence of brucellosis and losses due to it, particularly in dairy herds and in beef cattle in the more accessible parts of the country. As well as protecting cows from infection, Strain 19 reduces the risk of abortion in animals that do become infected. However, as it is only about 70% effective in preventing infection, it does not provide the means on its own to eradicate the disease; all it can do is reduce brucellosis prevalence to a low level — about 2% or below. This had been achieved over much of Australia when the national BTEC campaign started in 1970, although in some remote areas up to 17% of animals were still infected. Only a test-and-slaughter effort could finish the job.

The national campaign was launched with optimism — bolstered by the example of the campaign against bovine pleuropneumonia. This began in 1961; progress was so swift that the last observed lesion associated with the disease was detected just 6 years later. After a further 5 years of monitoring, Australia was declared pleuropneumonia-free in 1973. Bill Gee, who played a key role in the national coordination of BTEC as Director of the Australian Bureau of Animal Health from 1974, suggests the success of the pleuropneumonia campaign may have given the proponents of TB and brucellosis eradication false confidence. He says the nature of pleuropneumonia, and the availability of a good vaccine and a good test, made its eradication relatively quick and easy.

Nevertheless, there was no lack of appreciation of the magnitude of the job ahead — although early emphasis was on the difficulty of eradicating brucellosis rather than TB, which, in the end, proved the tougher adversary. As the third annual BTEC Progress Report, for 1976–77, put it: ‘The brucellosis eradication campaign is the most complex animal health program undertaken in Australia. While the disease itself and the control technology are complex, it is the sheer size and scope of the operation which create the real complexities. The campaign involves eight State and Territory organisations in the screening of 20 million breeding cattle run under a variety of management conditions not matched by any other single country in the world.’

The brucellosis effort combined vaccination to contain the disease with eradication by test and slaughter. Most herds went through two or three routine rounds of testing of all breeding animals. When an infected beast was found, the herd was quarantined and subjected to regular tests and culling until two tests, 6 months or more apart, indicated that all was well. A further check test was performed after another 6 months. As Australia had, in the early 1970s, some 18 million breeding cattle in about 180 000 herds, testing for brucellosis was clearly no small task. Abattoir monitoring and milk testing were also used to check for the disease, with trace-back systems linking any positive samples found to the herds they came from. Complex restrictions on the movement of cattle were imposed to protect clean herds from the disease.

On the face of it, the job required to eradicate bovine TB looked much more straightforward. Thanks to the programs that had already been implemented in all States, the first BTEC Progress Report, covering activities to March 1975, was able to record much lower prevalence figures for TB than for brucellosis — notably 0·007% compared with 2·9% in New South Wales and 0·006% compared with 1·5% in Victoria. Between them, those two States accounted for about 46% of Australia’s cattle in 1975.

The situation was somewhat similar in South Australia’s 6% of the nation’s cattle (TB 0·04% and brucellosis 1·8%) and in Western Australia’s 8% (TB 0·03% and brucellosis 0·13%). However, in Queensland, the State with the biggest cattle population — one-third of the total in 1975 — the TB figure was considerably higher at 0·6%, and the brucellosis prevalence was put at 1·5% in the south and west and only 0·2% in the north-east. This pattern was repeated in the Northern Territory, which at that stage accounted for just over 4% of the nation’s herd. There, the TB figure was 0·4% and the brucellosis prevalence 1·1 % in the southern region and just 0·04% in the north. Tasmania, with 3% of Australia’s cattle, was free of both diseases.

As with brucellosis, eradication of TB required repeated testing of infected herds and the slaughter of animals that tested positive. At least four clean tests were generally required before an initially infected herd achieved the final ‘confirmed free’ status. Detection of infected carcases by abattoir meat inspectors and trace-back to the herds of origin played a vital role in identifying infected properties, and movement restrictions were enforced to prevent infection of clean herds.

For the cattlemen, vets, stock inspectors and others involved in the campaign, the ground to be covered and the sheer number of tests required made it a vast, difficult and often tedious undertaking. Testing had to be timed to fit in as far as possible wit...

Table of contents

• Cover
• Title
• Copyright
• Table of Contents
• Foreword
• Acknowledgments
• Chapter 1. Something to Celebrate
• Chapter 2. Before BTEC
• Chapter 3. Getting Started
• Chapter 4. Up and Running
• Chapter 5. Eyes North
• Chapter 6. Brucellosis Succumbs in the South
• Chapter 7. TB in the South — a Protracted Send-off
• Chapter 8. The Campaign in the Centre
• Chapter 9. Queensland — BTEC’s Biggest Challenge?
• Chapter 10. To the Top End and Kimberley
• Chapter 11. Looking Back — and to the Future
• Appendixes
• Source documents
• Index