Compassion for the health of farm animals in 2003

Introduction

What can be the consequences of our lack of compassion for farm animals in Britain? I believe the answer to this question may bring a few surprises to those unconnected with farming. It does not seem possible on first thoughts that there should be anything amiss in this nation of animal lovers. I have found there are fundamental problems unresolved in the care of farm animals since I left the city to become a farmer to conserve a biodiverse environment in October 2000.

My working origins are quite other than farming and environmental conservation - I have lived and worked in the inner city almost all my adult life. Yet I am typical of the movement of urban people out into the countryside. I bought organic food and glass-bottled mineral water as part of my drive to restore my health after cancer treatment, I also take nutritional supplements, vitamins, trace-elements and anti-oxidants. Each dream that is lived in the countryside by the urban human outwash is informed by past lives, mine as a clinical virologist and doctor.

Vaccination strategies for health

I find the strategies for health of humans in our society, modern Britain, have been neglected or disregarded by the veterinary establishment for farm animals - BSE was the start of the consequences of so doing. DEFRA and the veterinary establishment have failed to recognise that humans are animals too. The farm animals must be as remarkably similar on genetic analysis to humans as mice have proven to be. The control of disease by killing farm animals is promoted unashamedly and no apology made for failing to apply methods in human medicine to the care of farm animals as in the FMD epidemic of 2001.

Vaccination of wild animals against rabies and classical swine fever

For FMD the veterinary establishment and DEFRA have not agreed that vaccination to live should be the primary response to an outbreak. The advice of the Royal Society and EU inquiries have fallen on deaf ears blocked by the cotton wool of defensive self-justification. In Germany the success of the vaccination of wild foxes with bait containing live attenuated rabies virus as oral vaccine has proven so successful in eliminating rabies from the fox population that they are now to apply this strategy to classical swine fever. Bait containing live attenuated classical swine fever virus is being put out for wild boar. Within the space of about 3 months they have already 60% vaccine induced immunity in the target population. The plan is to prevent outbreaks of classical swine fever in farm pigs by eliminating the circulation of virus in wild boar on the other side of the fence. But here we are still focussing on killing foxes with poison if rabies were introduced into British foxes hence the experiments on poisoning foxes in Scotland.

Vaccination against bovine TB

Could we use BCG, the live attenuated mycobacteria vaccine first developed by Camille Guérin, called "Bacille Camille Guérin", BCG? This was derived originally from Mycobacterium bovis the cause of TB in cattle. I believe we could - at the very least we could embark on a usefully large field trial in badgers and cattle in a TB hot spot. Farmers with cattle, even closed herds, are finding infection in their herd when brought in cattle or cattle contacts are excluded which can only come from local infected badgers. Infected badgers die a miserable death from Mycobacterium bovis. Thus cattle and badgers should be considered in any attempt to control and eliminate bovine TB.

I have been to a lecture given by Dr Doherty from the Staatens Institute in Denmark that manufactures BCG and PPD, a purified protein derivative. He has worked on human and animal infection with Mycobacterium bovis. Badgers can be immunised orally with BCG, they love chocolate so Dr Doherty suggested they could be given chocolate containing BCG, "badger chocolates". Cattle can also be immunised, more practically by subcutaneous inoculation as in humans - it will cause an ulcer at the inoculation site in them as it does in us. The immunity is at least partially protective.

PPD is used as a specific skin test for immunity, the TB-test in cattle, the Heaf test in humans. A vaccinated bovine, human or badger will make a small lump in the skin as response to PPD (this is due to the helper T-cell specific response signifying it has seen this particular protein before) as will one who has been infected in the past whether the infection be dormant or active. The solution in distinguishing vaccinated from infected animals is similar to that in FMD.

Just as the killed (inactivated) FMD vaccine is in effect a marker vaccine as it has been purified excluding the non-structural viral proteins so it turns out that BCG is also a marker vaccine. In the steps now lost in the mists of time which led to the isolation of an attenuated live bacteria called BCG (one able to elicit immunity but not cause disease) proteins were lost that are present in Mycobacterium bovis. These proteins can be used in an in-vitro test for T-cell response specifically to the lost proteins. Gamma interferon is secreted by T-cells that have been previously exposed to these particular proteins and can be accurately measured. The presence of gamma interferon in the test indicates the animal has been infected with Mycobacterium bovis at some point in the past. Such a test has been licensed by the FDA for use in humans and has been developed for cattle. The tools of modern medicine are there to be used to combat the spread of Mycobacterium bovis and ultimately to eliminate the infection.

Using imperfect vaccines - rabies vaccine with specific immunoglobulin

No vaccine works perfectly. Whilst scientists on the Royal Society Inquiry may believe that such a one could be developed there has been surprising success using imperfect vaccines, such as small pox. There is only one vaccine in human medicine that can be made to work perfectly in preventing disease in all instances, and it is thought also to prevent replicative cellular virus infection. This can only be achieved by the simultaneous administration of specific anti-virus immunoglobulin. This is immunisation against rabies. The rabies human diploid-cell derived vaccine killed or inactivated by beta-propriolactone is safe and potent. It is a simple vaccination IM or intradermal, and after exposure to rabies a course is given in conjunction with anti-rabies antibodies contained in human immunoglobulin derived from a vaccinee. (This is an opportunity to make sure my readers understand this and discard out of date notions of a painful and dangerous series of injections they would fear to undergo) All human cases of rabies will die (there are 3 attested recoveries published in the literature but it is not beyond doubt that these 3 persons had rabies). There has never been a death from rabies when the correct prophylaxis is given promptly after exposure with vaccine and immunoglobulin of attested quality and the course completed. This is a tremendous achievement in medicine but not applied to the thousands of persons who die of rabies each year in India or Africa.

Surely we should not wait for perfect vaccines before applying them to animals when we have taken such favourable advantage for our human selves. Doctors of human medicine are pragmatic, and humbled by the success of the imperfect vaccines they have had the good fortune to be able to use and receive. The single area in the health of Britain that has shown an very significant improvement in morbidity and mortality since the inception of the NHS in 1948 (when I was born and my employer throughout my working life) is in that of infection. Vaccination and the control and elimination of infection that it has afforded is not the least part of this improvement in health and life expectancy. Doctors have been dependent on scientists for these advances and remain so. Indeed in human medicine in Britain the scientists working on infectious disease continue to make significant international contribution to progress more so in this than in any other area.

Badgers, cattle and the reality of a control and elimination programme for TB

Whilst human medicine tries to put these benefits into practice in Britain it is clear to me that their veterinary colleagues do not. Can we be a civilised society whilst there is this discrepancy? It is not easy to take those steps that put it into practice, even a pilot study, and learn how it can most successfully be applied and then to carry it through, this includes educating and persuading the population, in this instance the farmers. A pilot study to control the spread of Mycobacterium bovis in a TB hot-spot area will require a careful strategy backed up by appropriate sampling and testing of both badgers and cattle. Commonsense measures such as TB-testing any cattle sold out of or into the area would be an essential component of any plan. Infected cattle and badgers would have to be weeded out by culling because treatment takes 6 months with multiple drug therapy throughout, in isolation whilst still shedding Mycobacterium bovis, not possible for cattle or badgers. Vaccination doesn't treat TB nor in all instances does it prevent infection so if possible the burden of infected animals should be removed, easier for cattle that for badgers. The first response to an infected badger set or herd of cattle would be BCG vaccination. As well as testing individuals for infection genetic sequencing of strains of Mycobacteria bovis can be used as in human medicine to track the relationship of infection in an outbreak, to a common source, multiple sources or the reactivation of infection acquired years ago. The ultimate goal of the plan would be to control and eliminate Mycobacterium bovis from all potentially infectable species: cattle, badgers and humans.

Scrapie, the EU and Britain contrasted

Even in scrapie elimination, Europe would seem to have a more sensible policy than Britain. This is an infectious disease not amenable to vaccination as there is no immunity elicited in an infected sheep. The virtue of the European plan is that genetic diversity is maintained in scrapie free flocks (those not reporting any disease); the majority. Scrapie is spread only by close contact among sheep and perhaps from the soil they contaminate upon death or lambing with the infectious material believed to be prions. It must be cheaper for government to investigate thoroughly an infected flock than apply genetic testing generally to hundreds of thousands of sheep most of whom are not at risk because they will never be exposed. Focus on eliminating infection where it exists is more elegant than the broad brush measures in the UK. The UK policies seem upside down because where vaccine can be widely and cheaply applied for the purposes of control and elimination of infection it isn't but genetic testing and selective breeding is to be applied across the board, a slow and relatively expensive policy compared to that proposed by the EU. Short tailed sheep, primitive breeds, could be irreparably genetically depleted (such as Herdwicks) in the attempt to select for scrapie-resistant genotype and some breeds rendered extinct (such as the Soay).

In the foreseeable future a test on blood that can sensitively and accurately predict scrapie infection will be available so that flocks can be tested and regardless of genotype be attested scrapie-free. The European policy seems to be the most elegant and the cheapest one whilst awaiting the day when we can test for scrapie infection ante-mortem.

Organic farming and prevention of disease

Whilst I find that I cannot respect the veterinary establishment and DEFRA for condemning out of hand modern or different approaches to the control of infection I find I cannot respect the organic establishment either.

My simple urban assumption was that if farm animals, ruminants, are put out to grass in natural conditions, extensive rather than intensive, they must be healthy. Alas it is more complicated than this. Naturally enough this is so - I should have realized that. Farm animals are as subject to external and internal parasites, environmental and commensal infection as well as shortages of essential trace-elements and vitamins as we human animals were prone to suffer before civilised modern Britain and modern medicine. Then we were smaller and shorter, frequently suffered acute and chronic infections whilst burdened by parasite and on the whole died earlier largely because of infection and obstetric complications. We also suffered vitamin and trace element deficiencies, from Ricketts, vitamin D deficiency (obstetric complications occurred because of the deformity of the pelvis) and goitre due to iodine deficiency, almost universal in some places. Young and growing animals are particularly susceptible to infections and deficiencies. Even now the level of selenium intake in humans in Britain borders on being insufficient as selenium is exhausted in our old long cultivated European soils.

Experience as an organic farmer

I am an organic farmer and support the principle and wholly support the attempt not to use pesticides, hormones or antibiotics to stimulate growth, nor the feeding exclusively of prepared concentrates to replace eating natural food grass grazed in extensive rather than intensive pasture. This seems better for the environment, more humane for the animals, and I thought healthier for the animals too. However I have found that organic farming has a bad reputation for animal welfare amongst experienced farmers of livestock in upland areas and they largely reject organic farming on this basis.

Now I know why. It seems to me that 'twee' suburban wishful thinking as far as animals are concerned holds sway in the organic movement, and I fell prey to it too. But now I have 2 years organic livestock farming under my belt I know better. I have hefted local sheep that graze on in-bye land (the fields on my farm) and the mountain and indigenous breeds of cattle in my suckler herd that graze the unimproved conservation wet pastures. I have raised lambs for 2 years, the healthiest ewe lambs kept as herd replacements the others sold for breeding and the ram lambs to the abattoir for meat (the organic abattoirs are still too far away, an hour and a half transport time).

Illness in my lambs

I have found that indeed internal and external parasites, environmental and commensal infection and trace-element deficiency are a serious problem in my growing lambs. At least half of my lambs were severely affected and perhaps all are stunted in growth though some much more so than others. The lambs' short lives have been blighted by this and distressingly it is my management, guided by the organic recommendations, that is responsible for this.

If I had been permitted to follow the simple and established minimum recommended by the local non-organic farmer I employ, most of this would have been avoided. He worms his lambs at 6 and 12 weeks of age and this is sufficient to carry them through to the relatively clean pasture after harvesting silage and hay and they do not need worming again.

Soil and trace elements

I am in an upland area, less-favoured, and I have permanent pasture on old red sandstone soils. There are 2 types on the land I farm, a gley soil overlying glacial till (wet) and a typical brown earth, a shallow soil over shale (good draining). The mountain has different soil again, and is capped by dolomitic limestone. There is no one soil to adapt my sheep to so that the lambs would not suffer deficiency supposing that this could be done by selective breeding to make better use of low levels of a trace element. Physiology makes this impossible. The old red sand stone is very deficient in cobalt and zinc and relatively deficient in selenium and copper. On testing all my lambs were deficient in selenium, half in cobalt and unfortunately I did not have them tested for zinc as this requires special blood tubes. Copper levels were normal.

Internal parasites, worms

The trace element deficiency exacerbates the problem with gastrointestinal worms further compromising digestion, immune competence and general health. My lambs had parasitic gastroenteritis and were thoroughly sick before the vet came out because of diarrhoea and stunted growth. They had very high nematode and strongyloides worm burdens. The organic regulations permit treatment once there is disease but this is too late to restore full digestive health and growth in the lambs. They have blighted lives. I have met other organic farmers struggling with sickly lambs like mine. One who had been with the Soil Association for 15 years also came to the Moredun Institute presentation on worms together with his young vet. He also farmed on old red sandstone derived soil 100 miles distant and was reduced to injecting his lambs with vitamin B12 to remedy their disease. There we learnt that at least 90% of the ruminant worm burden is on the soil and will only be killed by hot dry weather desiccating the soil, the grass and the worm larvae. The eggs and larvae are hardy on the pasture in our damp and cold climate and the hypobiotic (hibernating) forms of worms in the animal ensure that it is hard to reduce this burden on permanent sheep pasture to a level safe for lambs.

Organic pasture and crop rotation

Organic mixed farms have the possibility of managing their animals with less worming and perhaps less requirement for trace elements than upland farmers with permanent pastures on more acid soils. Lambs are too young to form a strong immunity to gastrointestinal parasites. Ram lambs must go to the abattoir before 12 months old, before they are of an age to attain effective immunity against worms. The only way of providing clean or relatively clean pasture for lambs from May onwards when they start to graze would be to plough up those flatter more favoured and improved fields and provide a new grass ley in early summer, the aftermath, fresh growth in the fields harvested for hay, from mid-August and in autumn turnips or some other crop and perhaps a sheep pasture previously grazed by cattle in winter. This is a tall order for upland farms. The uncertain and wet weather makes crop growing more likely to fail and most do not now attempt it.

The immorality of not applying preventive remedies

I think it is inhumane to blight the lamb's life given our current state of understanding and availability of simple and specific remedy. Where is the science to show that giving an oral worming agent, not long persisting in the dung, and observing a double recommended manufacturer's withholding period before human consumption, exposes the consumer of the meat to any risk, indeed exposes them to anything at all? Nothing may be put on the species rich un-improved pastures. Trace elements can be spread on the improved pastures to remedy specific shortage. But why should one not add the trace element to the diet or give it as a bolus if this should be necessary?

The expense of pursuing organic recommendations

Every treatment on an organic farm must be justified by veterinary investigation and recommendation, a huge expense for each individual organic farmer to bear. Even when this is prevention of infection by environmental bacteria, vaccination here provides protection of that animal against disease playing no role in controlling and eliminating an infectious agent. Clostridial infections of sheep are examples of such infections, the bacteria are in the soil. In the case of commensal infection vaccination can also prevent disease. Pasturella bacteria are carried in the respiratory tract of sheep as we carry pneumococci and can cause significant loss from overwhelming haemorrhagic pneumonia too acute to recognise and treat. Treatment of environmental parasites prevalent in upland areas such as liver fluke are also necessary in over wintering lambs. It seems to me that every organic farmer should not have to reinvent the wheel but that modern medical commonsense should prevail along with practical consideration of what is achievable in each farming environment.

Conclusion and challenge

It cannot be claimed that organic lamb is healthier than non-organic lamb from upland farms if the organic lambs have low selenium and zinc, low B12, and are poorly grown because half starved by worms. We should never destroy 10 million farm animals again when vaccination against FMD could have prevented the destruction of 90%. Are we to sit and twiddle our thumbs while TB spreads to more and more farms? When will it come to my farm, or the badgers and farms next to my farm? Is killing the only answer to TB? Why should I purge my small flock of Herdwick sheep of scrapie susceptible genotype if there is no scrapie on my farm? Compassion in the form of preventive health measures can ensure the health of farm animals and those who consume them or have contact with them. Either economic farming considerations or prejudice obstruct compassion to farm animals on both non-organic and organic farms. I would like to know if there is anyone in DEFRA, veterinary science or the establishment in veterinary medicine and organic farming who is enabled to do scientific work on the care and raising of farm animals and who is planning to address the issues I have raised in 2003. Is there anyone out there?

By Dr Ruth Watkins BSc Hons, MSc, MBBS, MRCP, MRCPath
e-mail ruthwatkins@supanet.com

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Compassion for the health of farm animals in 2003

Article by Dr Ruth Watkins

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