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PREMIUM CATTLE HEALTH SCHEME
The Need for a Cattle Health Scheme
Certain infectious diseases reduce the efficiency
of production and adversely affect animal welfare in both dairy
and beef cattle. The presence of some of these diseases within the
national herd may also compromise consumer confidence in the final
product. The major way in which
infectious disease is introduced to a cattle herd is animal movement,
but many breeders continue to purchase high value breeding stock
of unknown health status. Indeed even the purely commercial beef
herd must buy breeding bulls.
Health schemes offer a way to overcome these
disease problems. Essentially a health scheme is a set of management
rules and a disease testing programme which shows whether or not
a particular disease is present in the herd. It also offers a way
to control and eliminate the disease from the herd that not only
improves the productivity of the herd but also allows the sale of
breeding animals known to be free of the disease in question.
The Premium Cattle Health Scheme (PCHS) focuses
on four diseases: Bovine Virus Diarrhoea (BVD),
Johne's disease, Infectious Bovine
Rhinotracheitis (IBR) and Leptospirosis. This
reflects the importance of these diseases not only within this country
but also worldwide. The Scandinavian countries have already successfully
taken steps to eradicate BVD from their national herd. Australia,
Canada and the USA have well established Johne's disease herd programmes
and Switzerland, Denmark, Finland and Sweden have eradicated IBR
while other countries have started to do so. If we fail to follow,
then once the BSE induced ban on the export of live cattle is lifted,
we will find our cattle are of an inferior health status and no
longer saleable in these countries.
Premium Cattle Health Scheme the Objectives
- To eliminate specific diseases from cattle
- To identify herds free of specific diseases
and to provide breeding cattle of certified health status
- To prevent the introduction of specific diseases
to herds free of the diseases
- To monitor changes in disease status to allow
timely control or preventive action to be taken.
Why Choose the Premium Cattle Health Scheme?
SAC Veterinary Science Division (VSD) has operated
a network of veterinary diagnostic laboratories throughout Scotland
for many years. During that time considerable expertise has been
built up and close links have been forged between SAC vets, the
farming communities and the vets in practice. SAC also has more
than 10 years experience in running National Health Schemes for
other ruminant species. We have a team of vets with considerable
practical experience of the diseases covered by the Premium Cattle
Health Scheme and believe we can provide you with the best advice
available. How Does the Health Scheme Work?
For each disease there is a testing programme
and a list of rules and conditions which must be met. You will find
outlines of each disease on this website under The Diseases and
Programmes. Your own vet collects any samples which are required
and certifies that the herd conditions are met. Once the test results
are known, SAC vets in conjunction with your own vet will offer
advice on what action is required. SAC vets will also issue certificates
once the herd has been shown to be free of the disease.
The Diseases and Programmes
BOVINE VIRUS DIARRHOEA (BVD)
BVD Screening and Eradication Programme
BVD Accreditation Programme and Annual Testing
INFECTIOUS BOVINE RHINOTRACHEITIS(IBR)
IBR Screening and Eradication Programme
IBR Accreditation and Annual Testing
Johne's Disease Control Programmes
Johne's Disease Monitored Free Programme
Leptospirosis Accreditation Programme
Milk Monitoring Progamme for BVD, IBR and Leptospirosis
Bovine Virus Diarrhoea (BVD)
BVD Screening and Eradication
Initial Assessment: Where the BVD infection status
is unknown we recommend that samples from 10 animals are collected
from each distinct management group in the age range 9 18
months. These are tested for the presence of antibody to BVD and,
if positive, it indicates that infection is active in the herd.
If negative it is the first step to accreditation. If animals are
sold off the herd before 9 months of age, calves in the age range
6-9 months should be sampled instead. In the dairy herd bulk milk
screens and first lactation screens can offer additional information.
Eradication: Once BVD infection is confirmed
in the herd all animals over 4 months of age are screened once and
then all animals born subsequently for a period of 12 months after
the removal of the last virus positive animal are also tested. This
is usually achieved through two tests 12 months apart. Animals are
individually tested for antibody and any with low or negative levels
are then tested for virus. Once virus positive animals are confirmed
by a second test they are removed from the herd.
We follow up to check the success of eradication
by repeating the testing described under the Initial Assessment
(above) on two calf crops. If these show no evidence of infection
the herd is considered free of BVD.
BVD Accreditation Programme
Accreditation follows on from either a negative
initial screen or after the eradication procedures are complete.
Testing is essentially the same procedure as the initial assessment,
repeated at annual intervals and, after two clear tests, the herd
is awarded the status accredited free of BVD infection.
Milk can be used to replace blood samples for
antibody testing in lactating cows and bulk milk samples can be
used as part of the accreditation procedure where the initial assessment
of the dairy herd shows no evidence of infection. In this latter
case three clear bulk milk tests at 7 month intervals allow accreditation
of freedom from BVD.
To maintain accreditation the same test procedure
described in the initial assessment is repeated each year. Bulk
milk samples or samples from first lactation cows are also tested
three times a year in the dairy herd.
Infectious Bovine Rhinotracheitis (IBR)
Infectious bovine rhinotracheitis is an acute
viral disease that principally affects the upper respiratory tract
and can lead to fatal pneumonia. In adult cows infection is associated
with a severe and prolonged drop in milk yield, reduced fertility
and abortions. The virus is usually shed in secretions from the
respiratory tract but can also be spread in the semen of infected
bulls. Once an animal has become infected it remains so, despite
the development of an effective immune response and thereafter these
animals can shed virus at any time in their lives when stressed.
Movement of such animals into a herd is often the source of new
infections. Vaccination is an effective means of control, but this
does not stop infected animals from shedding the virus at a later
The diagnostic test used on blood samples is
an antibody ELISA which detects the animals response to previous
infection. This test cannot differentiate between antibodies stimulated
by the wild IBR virus from those stimulated by the live
vaccines licensed for use in the UK. For this reason vaccination
using the vaccines currently available is not an option when seeking
to eradicate the disease from a herd.
However, when gene-deleted vaccines become available
in the UK, it will be possible to distinguish between positive antibody
reactions caused by exposure to wild IBR infection and those caused
by the gene-deleted vaccine. This will change the whole approach
to IBR control, as vaccination will then become an option when attempting
to eradicate IBR from a herd, and the IBR programme will then be
Despite the effect this disease has on animal
health and productivity its main significance is as a barrier to
the export of live cattle to other regions or countries within Europe
which have already eradicated the disease. In future, in order to
gain access to these markets, herds will have to be able to prove
freedom from IBR.
IBR Screening and Eradication
Initial Herd Screen: In herds where the IBR status
is uncertain limited blood sampling or bulk milk antibody testing
can be carried out as an aid in deciding whether to progress with
eradication of this disease. Once you have decided to eradicate
the disease, all animals of 8 months of age or older must be sampled.
Animals which test positive are reactors and should be removed.
If there are too many reactors to remove in one go we will advise
on the appropriate strategy to follow.
Once reactors are removed a second herd test
is carried out between 3 and 12 months later. This is repeated until
a clear test is achieved.
IBR Accreditation Programme
To show freedom from the disease all that is required
are two clear tests of all animals of 8 months of age or over. The
second herd test can follow at 4 weeks and up to 12 months after
the first clear test.
Once accredited you must test a statistically
based sample of animals of 2 years of age or over each year.
Individual milk samples can be used to replace
blood samples in lactating cows.
This disease is a chronic, progressive, wasting
condition that affects ruminants and is caused by the organism Mycobacterium
avium subspecies paratuberculosis. Strains of the organism appear
to be specific to the different species of ruminants and if cross
infection does occur it does so rarely. The infectious agent is
shed in large numbers in faeces; it can be found in colostrum and
can pass into the womb to infect the developing calf. Animals are
infected by ingesting the agent and young animals are considered
to be the most susceptible to infection, however clinical signs
of diarrhoea and weight loss usually occur some time after 18 months
of age. In heavily infected herds this leads to a high rate of wastage
in cattle at two to four years of age. Infection is nearly always
introduced to a herd by purchasing infected replacement breeding
stock, including bulls.
The absorbed ELISA for the detection of serum
antibody (blood test) and the culture of the bacterium from faeces
are both valuable tests for the diagnosis of Johnes disease.
However, they can only be used to detect infected animals in the
later stages of the disease, once clinical disease becomes apparent
and for a short period prior to this.
This means a simple test and cull programme is
not enough and it must be supplemented by the removal of offspring
of any positive dam from the breeding herd in an effort to exclude
animals before they show signs of the disease. Because of the difficulties
with testing and because the infection can survive in the environment
for a limited time, control and eradication is more difficult than
for the other diseases in the scheme. However the on-going losses
due to the disease and the risk to herds purchasing cattle from
infected herds means that an effort should be made to eradicate
the disease from infected herds.
Vaccination is useful in heavily infected herds
to reduce the number of cases and therefore to reduce the amount
of infection in the environment. Vaccination will not remove the
infection from the herd, but it is an aid in the control of Johnes
disease. There is likely to be an increasing need for herds that
sell breeding stock to be accredited free of Johnes disease.
Johne's Disease Control
Herd Test: For Johnes disease all animals
of 2 years of age and over are blood sampled. In herds where there
has been no previous evidence of the disease we would follow up
any positive animals by examining faeces for the organism. Otherwise
all reactors are removed. The offspring of any cows which react
should also be removed from the breeding herd and their current
calf not retained for breeding.
The herd test is repeated each year, although
for maximum progress this interval can be reduced to six months,
until a clear test is achieved.
Johne's Disease Monitored
To be monitored free from disease two clear tests
of all animals of 2 years and over are required at an interval of
one year. As the incubation period for Johnes disease is measured
in years it is not possible to give an absolute assurance of freedom
from infection until many years have passed. That is why the programme
is called Johnes disease monitored free.
The herd test is carried out every second year
and all cull cows are tested in the intervening year. Where it proves
impractical to test cull animals a full herd test must be carried
(Milk samples cannot be used to replace blood
in the tests for Johnes disease.)
Leptospirosis is associated with infertility and
abortion in both beef and dairy herds and has been identified as
a cause of milk drop. The disease is caused by the organisms collectively
referred to as Leptospira hardjo (L. borgpetersenii serovar hardjo
and L. interrogans seriovar hardjo). After infection these bacteria
localise in the reproductive tract and in the kidneys. The agent
is passed in urine and infection spreads when cattle are exposed
to urine from infected animals. As with other diseases included
in the PCHS, disease is nearly always introduced into the herd by
the purchase of infected cattle. Infection may also be introduced
by contaminated water supplies. L. hardjo can be maintained in sheep
but does not appear to cause disease in sheep; however, sheep may
be a source of infection for cattle.
Of more importance is the risk of infection in
man, where infection causes flu-like symptoms and severe headaches.
Dairymen working in the parlour are most at risk of exposure to
infected urine. Herd owners must therefore be aware of their responsibilities
under the COSHH regulations.
Confirmation of infection in premature or stillborn
calves is difficult, but evidence of infection in the herd can be
gained by blood sampling the cows. In the scheme the ELISA test
is used to detect antibody in the blood or milk. Some cows only
test positive for a short time after infection. Another problem
lies in the fact that other types of Leptospira organisms can infect
cattle and result in a positive blood test while causing no disease.
These two features mean that a test and cull policy
is not a reliable option for control. But where testing in a herd
shows no evidence of disease, breeding stock from a herd can be
considered to be free of infection and be purchased safely. It is
for this reason that some herds may wish to pursue accreditation
of freedom from disease or monitor for the presence of disease.
Where a herd test shows evidence of infection
some owners may wish to enter a monitoring programme to help them
manage the disease. Alternative options for a herd with evidence
of active infection include vaccination and medication.
Once a herd is infected with leptospirosis, vaccination
is the recommended route to follow. We do not offer an eradication
programme for this disease.
To show freedom from this disease all cattle
of 2 years of age or older and all animals intended for breeding
that are one year or older are tested twice at an interval of 3
to 12 months. Thereafter each year a statistically based sample
of animals of two years and older must be sampled.
Individual milk samples can be used to replace
blood samples in lactating cows.
Milk Monitoring Programmes
for BVD, IVR and Leptospirosis
These programmes are based on the examination
of milk samples at three month intervals for antibody to BVD, IBR
or leptospirosis. The results can then be used by the herd manager
and his veterinary surgeon in the assessment of herd health and
fertility. A change from a negative to a positive result can be
used as a trigger for implementation of further control programmes.
(At present the tests for Johnes disease
cannot be used with milk samples)
An Outline of the Rules for the Premium Cattle Health Scheme
Screening and Eradication Programmes for BVD, IBR and Johnes
We advise herds to follow both the rules of the
PCHS and the principles of Herd Health Security. If this is not
done then any effort made in screening and removal of reactors will
yield little in the way of long term benefit.
Accreditation Programmes for BVD, IBR and Leptospirosis and Johnes
Disease Monitored Free Programmes
As herds will be certified either free of infection
or in the case of Johnes disease the disease itself,
it is imperative that all PCHS rules are followed and the principles
of Herd Health Security embraced. Failure to do so will not only
jeopardise the health status of the herd, but will prevent certification
of accreditation of freedom or monitored free status.
Monitoring Programmes for BVD, IBR and Leptospirosis
In these programmes there is no need to follow
any of the PCHS rules or adhere to the principles of Herd Health
Security. However, our firm recommendation is that by doing both
the health of the herd will benefit.
Rules : The Summary
A herd is defined as cattle that are under a unified
management system not necessarily on one premises.
Farm boundaries must prevent cattle from straying
off or onto the farm and must prevent nose to nose contact over
fences or walls. Double fencing with a space of 3 metres between
their cattle and neighbouring cattle is required for BVD and IBR
Purchased cattle that are of an inferior health
status either from within or without the scheme must enter quarantine
for the required period and be tested by the appropriate test(s)
for the disease(s) in question.
Equipment, livestock trailers and handling facilities
that are shared between health scheme cattle and other livestock
or non-health scheme cattle must be cleaned and disinfected before
use by health scheme cattle.
Suitable quarantine facilities in the form of
pens or paddocks which do not allow contact with other farm livestock
must be available for cattle coming into the herd. These facilities
must conform to part 2 of the Herd Health Security Document.
Samples can only be collected by:
i) a veterinary surgeon
ii) someone designated by the veterinary surgeon who is not the
owner of the cattle nor an employee of the owner
iii) in the case of milk samples by the milk recorder.
Where the herd uses more than one bulk tank, representative
samples must be collected from each tank and tested separately.
Any disease condition which might be attributable
to the disease which is the target of the programme must be investigated
by the owners own veterinary surgeon.
It should be recognised that any contact with
other stock puts the status of the herd at risk. As there is no
PCHS accredited section at cattle shows and sales any accredited
cattle attending a show or sale will be deemed to have lost their
accredited status. On being returned to the herd of origin such
animals must be treated as non-accredited animals and must be isolated
and tested according to the requirements of the individual disease
SAC Veterinary Science Division strongly recommends
that members veterinary surgeons should be members of the
British Cattle Veterinary Association and attend SAC Veterinary
Science Division Premium Health Scheme vet workshops.
Herd Health Security means the measures taken
to prevent the introduction of infectious agents which cause specific
diseases in a herd of cattle.
Any cattle from herds of unknown disease status
must be assumed to be a potential source of disease.
Health Security can never be absolute, however,
the risk of introducing disease is directly related to the extent
of the measures taken and the degree to which they are applied
Health Security : General Measures
These are measures applicable to the control of
most infectious diseases; they represent good husbandry standards
and adoption should be attempted by all health conscious cattle
1. Where it is necessary to purchase replacement
stock avoid infected cattle by acquiring from herds certified free
of specific diseases (i.e. accredited).
2. Quarantine facilities should be provided for
all added animals. These should prevent contact with other stock
and neither air space, drainage nor dung storage should be shared
with other cattle. A dedicated building separate from other cattle
buildings is ideal, but a separate paddock which prevents contact
with other stock may suffice. It is also advisable to discuss with
your vet any screening tests which must be carried out and ensure
that animals are inspected regularly for signs of disease. A quarantine
period of 4 weeks is sufficient for most diseases.
Dung from the quarantine facility should not
be disposed of onto pasture which is to be grazed by cattle within
12 months. Similarly where paddocks have been used for quarantine
purposes they must not be grazed by other cattle within 12 months.
3. Avoid all contact either direct or indirect
(e.g. dung or urine) with cattle from infected farms (e.g. at shows,
at markets, in transit, over fences, on rented grazings). Where
contact has occurred animals should enter quarantine on return to
4. Avoid introduction of infection on clothing
or footwear (e.g. AI technician, vets, neighbours, hoof trimmer)
or equipment (e.g. vehicles, crushes, dosing equipment). Dedicated
clothing, footwear and equipment for a particular farm are the safest
option. A less secure though acceptable alternative is thorough
cleaning and disinfection of clothing, footwear and equipment before
use on the farm at risk. Single use disposable overalls and disposable
foot covers should be used for casual visitors. Vehicles should
be cleaned and disinfected with an appropriate disinfectant before
they are used for cattle unless they are moving direct to a slaughter
house. Particular effort should be made to clean and disinfect any
equipment likely to be contaminated with blood (e.g. hoof knives,
instruments for castrating, disbudding or dehorning). Injection
equipment should never be shared between farms. Veterinary surgical
equipment must not be shared between farms unless it is sterilised
5. Limit farm access to those people deemed essential.
6. Limit and control access of vehicles to the
farm. Delivery and pick up points should be at a site isolated from
the cattle and at the boundary of the farm. Where possible the driver
should remain in his cab and should certainly never assist in removing
cattle from pens unless using farm dedicated overalls and footwear.
7. Use piped mains water rather than natural water
sources whenever possible.
8. Prevent access of vermin and wildlife to feed
and bedding stores and the cattle whenever possible.
9. As purchased feed and bedding constitute a
risk of introducing infection it is important to use reputable suppliers.
10. Embryos and semen should be from donors of
disease free status.
11. Sheep can harbour some of the diseases which
affect cattle and therefore contact between cattle and sheep should
be avoided. This is particularly important at housing when cattle
should not share the same building with sheep. If at all possible
cattle and sheep should not graze together. The dung from sheep
sheds should not be spread onto fields to be used for cattle and
cattle should not be allowed access to water courses which have
sheep grazing upstream.
Measures to prevent introduction of infectious agents causing
If the introduction of specific diseases (e.g.
IBR, BVD, Leptospirosis or Johnes disease) is to be prevented,
such as in a health scheme, the health security must be tailored
to these diseases. Details of specific preventative measures for
diseases included in the Premium Cattle Health Scheme are found
in the comprehensive set of rules available on request. Most of
these measures are in fact included in the Health Security : General
Measures page, however, different routes of spread are more important
for some diseases than others. For example, airborne spread is much
more likely with IBR than Johnes disease. So there is a requirement
in the rules for 3 metre spaced double fencing bordering neighbouring
farms for the IBR scheme but not the Johnes disease scheme.
A quarantine period of 4 weeks suffices for IBR, BVD and Leptospirosis
but not for Johnes disease where 4 months is required.