The components of a biosecurity program are all good
management practices that can increase the profitability of your
sheep farming operation. A good biosecurity regimen should always
be in place to improve your farm efficiency, protect neighbouring
farms and the countryside, and safeguard animal and human
Biosecurity is not just to
protect farm animals; it is also to protect you, your family and
your farm workers. Disease is not always apparent, especially in
its early stages. Any person visiting a sheep farm and not carrying
out effective biosecurity measures on entry and on leaving a
premises runs the risk of spreading diseases to or from that
Fig 1: These purchased sheep are incubating
diseases that could have devastating effects on your farm
diseases can be spread between sheep farms
Introduction of diseased
Introduction of sheep
Introduction of healthy
sheep that have recovered from disease but are now
clothing and footwear of people (veterinarians, contractors, other
farmers, salesmen, service personnel) who move between
Feedstuffs, especially high
risk feedstuff which could be contaminated with
Impure water (surface
water, streams and rivers etc.);
Manure handling and
aerosolized manure and dust; and
Other species such as dogs,
cats, wildlife, rodents, birds and insects.
Fig 2: A key biosecurity objective is to prevent
(or minimize) cross-contamination of an animal's infected body
fluids (products of abortion, faeces, urine, saliva, respiratory
secretions, wool etc.) to other animals, feed and
What is biosecurity?
biocontainment are words describing programs for infectious disease
- aims to reduce/prevent the introduction of new diseases onto a
farm from outside sources. Alternatively, 'biosecurity' is the
prevention of disease-causing agents entering or leaving any place
where farm animals are present.
Biocontainment - aims to reduce/prevent the
movement of infectious diseases on the farm
Biosecurity has four major components:
Select all necessary purchased sheep from
known sources and/or health status to reduce the risk of
Isolation. Strict isolation prevents contact
between groups of sheep after arrival on farm and reduces the risk
of spread of infectious agents.
Movement control - includes all vehicles,
animals, and people traffic that could introduce infection onto
Sanitation. - the disinfection of materials,
people and equipment entering the farm and the cleanliness of the
people and equipment on the farm.
Fig 3: Is abortion in my flock costing me
Know the health history of
the flocks from which sheep are purchased.
Know the health status of
sheep brought into your farm.
Never bring in sheep without
knowing their vaccination history
Limit purchases to ewe lambs
and gimmers, not older sheep
Quarantine all new arrivals
for at least 30 days and preferably until after lambing
Ensure that sheep do not
share community pastures/common grazing
Ensure that sheep do not
share fence lines with neighbours' sheep.
Ensure that methods of
working are designed to minimise where possible the movement of
people, vehicles or equipment into areas where sheep are
Keep a record of visitors to
Fig 4: Is this feed store
Fig 5: Which parasites could this
Scottish halfbred ewe-lamb have introduced onto my
Attempt to prevent manure
contamination of feed.
Use different equipment to
feed and to clean pens or completely clean between
Routinely clean and
disinfect feeding equipment and sheep handling/shearing/foot
Never step in the feed
Transport sheep in clean
vehicles, preferably your own.
Loading area is located at
the perimeter of the farm.
Collection of fallen stock
is located at the perimeter of the farm.
Fig 6: "I have never had to drench my purchased
gimmers before." (See below)
How do I design a biosecurity program?
As part of your flock
Develop a written risk
assessment of your farming operation, facility and management
With the help of your
veterinary practice identify the level of any infectious diseases
already existing on your sheep farm.
Identify and prioritize in
writing those diseases targeted for control through your
Assess the diseases not
present on your operation and prioritize those you wish to continue
Review your facilities with
your veterinarian to determine the risk level for disease
transmission or movement and write down a prioritized list of
Work with your veterinary
practice to develop a written biosecurity plan that meets your
Inform all farm staff how
to implement the plan.
Review and update this
written plan on an annual basis.
Biosecurity at livestock markets and
The spread of disease is a
serious risk at livestock markets, where animals come into close
contact with other, potentially infected, livestock or equipment.
There are a number of measures which should be taken to minimise
Do not bring onto or take
off the market any vehicle, equipment or clothing contaminated with
Do not leave the animal
area without cleaning any contamination from your
Do not leave the animal
area without cleansing and disinfecting your boots
266 KB) contains information for everyone entering a farm on which
livestock is kept to minimise the spread of disease.
Fig 7: Fluke-infested
liver from the gimmer featured above.
Fig 8 (above) & Fig 9 (below): "I have never
seen this foot disease until I bought that lot of store lambs"-
Contagious Ovine Digital Dermatitis (CODD)
Current advice from DEFRA
states that BTV8 vaccination in England and Wales is the only
effective way for individual farmers to protect the welfare of
their animals and their own livelihood against Bluetongue
(compulsory vaccination presently operates in Scotland). The
nature of this disease is such that keepers cannot rely on their
neighbours' vaccination: midges can be carried by winds and by
human activity. The only sure way to protect against Bluetongue is
for farmers to vaccinate their own animals.
All purchased sheep must be
treated for internal parasites (parasitic gastroenteritis; PGE) and
liver fluke (based upon risk) immediately upon arrival on the
All introduced sheep should be assumed to be sources of
multiple anthelmintic resistance and be treated with an effective
anthelmintic on arrival and yarded for 48 hours to ensure that any
viable nematode parasite eggs have been voided before they are
turned onto pastures which might be grazed by sheep within the next
6 months. The current options are to use a combination of
anthelmintic drugs with different mechanisms of action (a group III
macrocyclic lactone (ML) and levamisole [group II]), or
Triclabendazole is highly
effective at killing all stages of flukes responsible for acute
fasciolosis. Nitroxynil, closantel, and oxyclosanide are less
effective against immature flukes and should be used only in the
treatment of subacute and chronic fasciolosis.
Plunge dipping in diazinon
dips kills scab mites within 24 hours and provided that sheep are
correctly plunge dipped affords residual protection for several
weeks. This method has the added advantage of eliminating louse
Two subcutaneous injections,
seven days apart, of 200 µg/kg ivermectin, provide effective
control of sheep scab. A single intramuscular injection of
doramectin at a dose rate of 300 µg/kg of doramectin achieves some
persistence but may occasionally be insufficient to provide
protection against re-infection for the whole 17 day period during
which the scab mite can survive off the sheep. A single
subcutaneous injection of moxidectin at a dose rate of 200 µg/kg
provides residual protection against sheep scab for at least 28
days, although the UK data sheet recommends two injections 10 days
apart for the treatment of disease outbreaks. An alternative
treatment for lice is necessary.
Louse infestations can be
eliminated by plunge dipping or pyrethroid pour-on
Contagious causes of abortion
Enzootic abortion of
ewes (EAE), Chlamydophila abortus
Freedom from C.
abortus infection is best achieved by maintaining a closed
clean flock with strict biosecurity.
Various accreditation schemes
offer breeding female replacements from flocks declared free of
C. abortus infection but careful consideration must be
given to establishing a clean but susceptible flock when the health
status of neighbouring flocks cannot be guaranteed. Vaccination
offers the best means of control for farms buying breeding
replacements from non-accredited sources.
(Salmonella abortus ovis) and Campylobacter fetus
subspecies fetus (intestinalis) and
Prevention is best achieved
by maintenance of a high health status closed flock; where this is
not possible purchased sheep must be kept segregated until after
Wherever possible sheep
producers should maintain a closed flock to prevent purchasing
diseased sheep. If purchases are essential, ewe lambs should be
bought from known sources rather than old ewes which are often
chronic carriers. All purchased stock must be quarantined for one
month and examined for footrot before introduction into the main
flock. Footbathing, in either 3 per cent formalin or 10 per cent
zinc sulphate, should be undertaken three times during this
Contagious ovine digital dermatitis
Contagious ovine digital
dermatitis has been introduced onto many sheep farms with severe
consequences in terms of numbers of sheep affected, severity of
lesions and poor response to conventional treatments.
Control of this condition
depends on regular inspection of all purchased sheep during the
quarantine period, the isolation of any sheep found to be lame and
prompt treatment with a suitable antibiotic recommended by your
veterinary surgeon. You should be aware that this may have to be
actually administered by a veterinary surgeon.
The treated animal(s) should
be re-examined at intervals to assess efficacy of
Respiratory tract diseases
Bacteria causing the common
sheep respiratory infections, such as pasteurellosis, are
ubiquitous and are best controlled by vaccination.
adenomatosis (syn: Jaagsiekte, pulmonary
Sheep pulmonary adenomatosis
(SPA) is a contagious tumour of the lungs of sheep. Disease
transmission is facilitated by close confinement and can be a
significant problem where sheep are housed for long periods during
the winter months.
Prevention can be effected by
maintaining a closed disease-free flock with double ring fencing.
Purchase of breeding replacement stock is the major risk factor.
Sourcing replacement stock from flocks free from SPA has obvious
advantages but confirmation of such status in the absence of
serological tests is not possible. Biocontainment involves housing
sheep for the minimum time and grouping sheep on age rather than
scanned litter size or lambing date wherever possible.
Shearing equipment and other
handling facilities, such as mobile plunge dippers and feeders are
much less important as vectors for disease than purchased animals,
which must be inspected before purchase and quarantined for at
least two months. The disease is characterised by suppurative
necrotising inflammation of superficial lymph nodes particularly
the parotid lymph node at the base of the ear.
The National Scrapie Plan no
longer operates in the UK. There are many more important diseases
upon which to base genetic selection. Purchase sheep from flocks
known to be free of scrapie but this is not a major
Visna maedi virus
Visna maedi virus (formerly
maedi visna virus). In countries such as the UK, MVV flock control
measures are limited to a relatively small number of pedigree
flocks. No specific control measures have been adopted by
commercial UK farmers for MVV. Purchase accredited pedigree sheep
where necessary but no such commercial sheep are
There is no practical method
to screen young sheep for Johne's disease and the best means of
controlling disease is maintain a closed flock or continue to
purchase stock from farms where disease has not arisen in their