A Wander in Vetland

by John Hicks

Modern society has, until very recently, placed great faith in the power of antibiotics to fight disease and, faced with outbreaks of infection, there still is the temptation to mass medicate and treat the whole flock. But these days there is greater awareness of the risks of such blunderbuss approaches, especially regarding the development of antibiotic resistance. Pastoral farming systems have not, for the most part, been tainted by this sort of misuse of drugs, although it has been common in housed animal, factory farming systems – especially with pigs and poultry. Besides, since Listeria can hang around in the environment, any benefit from mass medication on Larry’s farm would probably be temporary and the cost high.

  Sid and I visited the farm to see what was going on. Many of the paddocks were muddy. Larry had noticed that the lamb mobs were walking in circles and making matters worse by trampling the grass into the mud. It was this observation, plus the results of an analysis of puddle water – the only water available to these lambs – which led us to an explanation for their poor performance. Lambs need clean food and water. Because the paddocks were large, the lambs were being left in them for several days rather than being moved onto fresh, clean grass each day. This would have been fine in dry conditions, but in the wet they were tramping their food into the mud. They were circling restlessly because they were in search of clean food. The term faecal-oral transmission probably requires no explanation. Mud wasn’t the only foreign matter garnishing their diet.

  Normally, in wet conditions, lambs don’t drink much, there being sufficient water in their grass diet. However many of these lambs had enteritis, lambs with diarrhoea drink more, and the only source of water was from the puddles. Our tests revealed that these puddles contained coliform counts of over four thousand per ml, far above the acceptable limit of less than 100. The bore water on the same farm had a count of 12, so plenty of clean water was available, albeit at a price.

  The long-term solution for this farm lay not in drugs. Larry needed to subdivide the paddocks, so that the lambs could be moved more frequently onto fresh, clean grass. He needed to set up a system of water troughs so that they had access to clean water. Money also needed to be spent improving the drainage system across the farm. Good management is a far better way of preventing disease than masking poor management by misusing drugs. Unfortunately, the overheads involved in farming are little appreciated by the general public.

  ~

  Why would I choose to exemplify these two cases? Perhaps it is to show how the involvement of the veterinary profession in farming has changed over the years, years when the public’s perception of what it does has lagged several decades behind the reality. The emphasis has moved away from treatment of individual animals, to a more holistic consideration of the farm itself; from the losses due to clinical disease, to the hidden effects of sub-clinical diseases (diseases which produce no overt signs of their presence) on the productivity of the herd or flock; from intervention to prevention. We now have a much better idea of how healthy, well-fed farm animals should perform and what “best practice” procedures to put in place to attain optimum productivity.

  It’s a far cry from the early years of the profession, 250 years ago.

  Chapter Twenty-three

  Foot and Mouth, and the Detritus Gene

  Mr Sutton said the Reserve Bank had estimated the impact of a foot and mouth disease outbreak here as costing about $6 billion in GDP in the first year and about $10 billion in GDP in the second year.“So, it’s a hugely important area, and it’s crucial that everyone – individuals and groups – work together to ensure the response is as integrated and comprehensive as possible.” – Government release from the Minister of Biosecurity, Jim Sutton, April 2005.

  Veterinarians, in the 1790s were scarcely better than the quacks they were trying to displace. In 1897, in The Veterinary Record, William Hunting writing about the advances of the previous sixty years, still felt that the high position that the veterinary profession had attained during Victoria’s reign only marked “its arrival at adolescence”. He noted: In 1837 every wretched animal that was submitted to veterinary treatment underwent a course of bleeding, physicing and blistering … Professor Sewell asserted that bad feeling and ill usage might cause rabies in dogs … everyone believed that a healthy sign was… when a wound ‘mattered freely’ … men with the mere ability to read and write with difficulty could enter the ranks… twelve months study was all that was demanded.

  The Professor Sewell to whom William Hunting referred was obviously a controversial figure. It was Sewell who had, notoriously, prescribed ridiculous treatments for the new vesicular disease of cattle which made its appearance near London in 1839. This disease was, in fact, foot and mouth (FMD). Professor Sewell’s recommended treatment regimen (for a disease as untreatable now as it was then) included the usual catalogue of harmful intrusions: copper sulphate for the sore mouths and feet, blisters and bleeding, soda and ginger, calomel, and setons in the throat or dewlap. (Setons were loops of twine or tape sewn through the skin to encourage suppuration).

  A survey by the secretary of the Royal College of Veterinary Surgeons in 1848 which sought to categorise all the various people treating animals revealed that ...under the various denominations of horse-doctors, horse-surgeons, farriers, cowleeches, cattle-doctors, castrators, spayers and gelders, charmers, spell-workers, butty-colliers, water-doctors, and various other local appellations, those who gain a livelihood by the practice of the art... far exceeded those who had been to veterinary school. But perhaps, had Professor Sewell taught them, their veterinary training would have conferred little benefit to their patients in these early years.

  Showmanship came first. There must have been a marvellous sense of theatre about these bold treatments. After all, those Victorian vets had to impress if they were to elicit payment from stingy farmers and hard-bitten horsemen. It was not what you did, but how you did it – a lesson that is as relevant to new veterinary graduates today as it was then. No wonder if some of the public turned to far less injurious alternatives such as homeopathy, even if they, too, were ineffective. However, by the middle of the century, men of scientific integrity were starting to appear.

  The year 1865 (the very year Carl Volkner was murdered at Opotiki) finally showed the worth of a profession starting to embrace Pasteur’s research and understand the role of animalcules (micro-organisms) in the spread of disease. That is the year Cattle Plague (Rinderpest), thought to have been imported from Russia, killed an estimated half million cattle in Britain. It was only halted when veterinary measures – advocated but not adopted at the beginning – were finally put in place. Those who promoted the older theory of “spontaneous generation” which maintained that diseases appeared out of thin air – such as Viscount Cranbourne – were finally over-ruled. In Victorian Britain, things were always trickier if the aristocracy were not on your side. In the end, science prevailed and the Animal Health Division of the Ministry of Agriculture was established.

  Cattle Plague/ Rinderpest, the most severe infectious disease of cattle the world has ever known, was finally eradicated in 2011. This, by amazing coincidence, was the sestercentennial year since the founding of the veterinary profession by Louis XV in 1761, specifically to eliminate Cattle Plague.

  Unfortunately,there are many other threats: like FMD. Control of such highly infectious diseases remains the chief responsibility of the veterinary profession and it is the reason behind the continued government funding of veterinary education. The worst mistake a veterinary practitioner could ever make would be to miss a diagnosis of an “exotic disease” and place the whole agricultural economy of his country at risk. For New Zealand, where the largest portion of the country’s gross domestic product is generated by pastoral industries, the consequences of such a miss would be catastrophic. Vets in New Zealand have long proven their worth. As long ago as 1880 Messrs Richie and Naden eradicated a deadly outbreak of bovine pleuropneumonia in the Waikato. What would it be like to carry the blame for an erro
r of judgement in Southland in 1981 that had the potential to break the entire economy of New Zealand?

  Thoughts like these accompanied me as I drove out to AZ’s pig farm. AZ only had a couple of breeding sows and one of them had sores on its teats. Such a call-out would not, in the normal course of events, have raised my blood pressure. But this particular morning it did. The reason was that another pig farm near Temuka, a couple of hundred kilometres to the north of us, was currently at the centre of an FMD emergency. The whole of New Zealand was on a full scale alert because the pigs at Temuka had blisters on their feet and snouts and were under investigation by MAF. Movement controls were in force and samples had been sent to Pirbright, a laboratory in England specialising in FMD, for testing. The daily TV news was milking it for all it was worth. The economic future of New Zealand hung in the balance. Well done the vet who had raised the alarm! He had not failed in his line of duty.

  I knew that teat blisters could occur in pigs with FMD, although there would also be lesions on the snout and, possibly, the feet as well. AZ hadn’t mentioned these, but then he didn’t have a lot of experience of pig farming, having come to it as a self-sufficiency project late in life.

  AZ led “The Good Life” on the couple of muddy acres surrounding his dilapidated weatherboard house. There never seems to be a shortage of used wire mattress frames, broken prams or discarded refrigerators to patch up the fence holes on small-scale pig operations such as his; for AZ belonged to that sub-tribe of mankind who possess the “detritus” gene and are thereby rendered oblivious to their surroundings. They spend all their weekends and holidays at the local rubbish dump – battered flat-deck ute and recycled trailer at the ready – fossicking for free in their second-hand tea-cosy hats, soiled dungarees and holey gumboots. And a lifestyle which for me, and many others, would have presaged a bleak and sordid descent into old age, for AZ offered a treasure trove of beady-eyed opportunity: to save, scrimp and scrounge.

  In my mind’s eye I pictured crawling through a filthy, bodged-up pen of rotting, tip-salvaged doors to examine my new patient – just as I had on previous visits.

  FMD outbreaks often start in pigs. They are highly susceptible to the virus and it rapidly multiplies once it infects them. Pig farms then become virus “factories” from which plumes of infection arise and are spewed downwind. The virus can jump many miles like this, in addition to being carried by people, vehicles, on contaminated stockfeed and, of course, on and within transported animals.

  As I drove to AZ’s, I imagined what I would do if I found the sow with sore teats also had tell-tale vesicles (blisters) on her snout and round her feet, a raised temperature, and was starting to smack her lips and salivate as the sores made their presence felt. The correct procedures to follow in the event of a suspected diagnosis of FMD had been thoroughly inculcated in me on the “exotic disease” training courses I had attended a few years earlier. I checked my glove compartment to find the little card with the number of the MAF vet I would have to ring the moment I suspected the worst. I planned where I would park my car at the entrance to AZ’s drive to stop all movement on or off the premises. There were sure to be a couple of rusting fridges and a twisted trampoline or two to reinforce the barricade. And should my investigations reveal any hint of the presence of FMD on the farm there was the delightful prospect of being confined there for several days of squalor with the genial but disorganised AZ. It didn’t hold much appeal.

  My reveries were broken by a voice on the RT. “Vet base to vet 11”.

  “Go ahead Audrey”

  “AZ’s just rung to say he doesn’t need a vet any more. His neighbour reckons it’s just due to the sharp teeth of the piglets she’s suckling.”

  I did not feel any immediate sense of relief. What if the neighbour was wrong? Was it still AZ’s decision? I chewed it over.

  “OK Audrey, but I’ll have to discuss it with the RVO [Regional Veterinary Officer] to decide what to do next.”

  In the event, and much to my relief, the RVO assumed responsibility. So AZ was untroubled by my presence, but perhaps a little surprised when the RVO turned up just to confirm how much damage a suckling piglet can do to mum with those sharp little nippers. Better to be safe than sorry – about the pigs and the national economy, that is. As to the RVO, soon after this incident he left his job in Invercargill for a more exotic location in the Pacific Islands. It would be idle to speculate, but perhaps the move was expedited by his encounter with AZ and the detritus gene.

  The Temuka outbreak was interesting. No FMD virus was isolated from the affected pigs. Despite the blisters, they remained healthy and never ran fevers. The conclusion was that this was a case of parsnip poisoning. A similar condition had been reported among horticulture workers handling celery or parsnips, which, like some other umbelliferous plants, contain chemicals called furocoumarins in their leaves. These are absorbed into the skin and react with sunlight, releasing energy that damages the skin cells – hence the blistering. All that is required is the combination of pigs, parsnips and sunlight of a particular wavelength. The pathology of the disease was not clarified until the early 1980s – which only goes to show that there is always something new under the sun.

  FMD is an excellent illustration of why the New Zealand government should do all it can to preserve a vigilant veterinary presence throughout its rural hinterland.

  I remain eternally grateful that during my career as a farm vet I have never been involved with a genuine outbreak of FMD. If one should ever occur, the stresses for all concerned will be truly enormous.

  Chapter Twenty-four

  Science and Drama

  … slight disturbances precipitate attacks of continuous bellowing and frenzied galloping. The gait becomes staggering and the animal falls with obvious tetany of the limbs which is rapidly followed by clonic convulsions lasting for about a minute. During these convulsive episodes there is opisthotonus, nystagmus, champing of the jaws, frothing at the mouth, pricking of the ears, and retraction of the eyelids. Between episodes the animal lies quietly, but a sudden noise or touch may precipitate another attack. The temperature rises after severe muscle exertion… the absolute intensity of the heart sounds is increased so that they can be heard some distance away from the cow. Death usually occurs within half to one hour and the mortality rate is high because many die before treatment can be provided… from Veterinary Medicine. Third Edition, 1968: Blood and Henderson

  With this classic description of grass staggers in cattle, I salute a moment of high drama from the pages of Blood and Henderson, a textbook venerated by generations of vets and veterinary undergraduates, and more remembered for the apt name of one of its authors than its rather forgettable title. Large tracts of veterinary textbooks date as rapidly as scientific knowledge expands; but vivid descriptions of the presenting signs of most diseases remain valid for as long as they exist.

  During my life as a veterinarian, science has unravelled many of the mysteries of animal health. Practising vets, not just those who work in research, are in a great position to contribute to this body of knowledge. It is the duty of every vet not merely to treat and cure but, where possible, to investigate the underlying causes of anything unusual that comes his way – most have us have degrees in veterinary science, after all. Furthermore, he should make every effort to have his findings published for the good of all. Only when a problem has been revealed, and its causes discovered, can effective steps be taken to mitigate its effects or prevent it happening again.

  I was very fortunate in my first job in New Zealand to work under a principal who encouraged his vets to question and investigate. Hank de Jong had a research background at the Wallaceville Animal Research Centre but, after several years as a microbiologist, had been drawn back into veterinary practice. Aside from his work Hank could be absent-minded and, sometimes, impractical. These traits led to him inviting – without first asking Viv and me – a young veterinarian and his wife and their two pre-school children to stay w
ith us. We had only been in New Zealand a few weeks.

  It was a trying time because I was getting to grips with my new career in a strange country and Viv had just started a new job in Stratford, the neighbouring town. All our furniture and appliances were in transit from England. We were hardly in a position to play the part of gracious hosts. We were sleeping on the floor in our sleeping bags: no bed, no table and two borrowed kitchen chairs. On the other hand, this was kind-hearted Hank, who was so supportive of me, a new graduate, in my first encounters with the wild farmers of Taranaki. How could I refuse? I dreaded what Viv would think when I told her, but Hank had anticipated my mild objections and he offered to lend us some essentials, including a mattress from his open garage. The mattress smelled as though it had been a favourite lurk of the local cats and it was memorably flea ridden. I would have offended him had I refused it.

  In the event everything worked out well. John and Maureen Pauli became friends in adversity and we all rattled along famously in our nearly empty house, although Viv and their children were badly affected by the flea bites.

  John was doing research into hypomagnesaemia in cattle: low blood magnesium levels. These are found, most dramatically, in grass staggers. Hypomagnesaemia was a common problem on Taranaki farms during spring when the cows calved and came into milk. Cows are on a knife-edge when their magnesium levels are low and they needed only the slightest stress, if any at all – a spell of cold weather, a walk to the milking shed, another cow bullying them – to tip them into the convulsions which Blood and Henderson so vividly describes. It was something all farmers dreaded.

  If there was any chance of saving them at this point, they needed urgent treatment. This involved infusing a magnesium solution slowly into the jugular vein: not the easiest thing to accomplish on a powerful beast thrashing about mindlessly. If the distracted vet – dodging flailing hooves and bent on self-preservation – ran the magnesium into the vein too rapidly, the patient could go into cardiac arrest and die. Death never looked good when it was on the end of your flutter valve needle. If the treatment was too late the animal, exhausted and with major muscle damage, would relapse into a semi-comatose state from which she would never fully recover.