Livestock Biosecurity Factsheet
Current at 24 June 2013
Check for updates at agric.wa.gov.au
Arthritis in sheep
By Dr Roy Butler, veterinary officer
What is arthritis?
Arthritis means inflammation of one or more joints.
In Western Australian sheep, arthritis is usually the
result of infection with Erysipelothrix rhusiopathiae
bacteria. Arthritis usually causes lameness and
visible swelling of at least two joints in the legs.
Which animals are most at risk?
Young lambs are most susceptible to arthritis
infection. All breeds are susceptible, but arthritis is
more common in Merinos, probably because many
are both mulesed and shorn. Mulesing and
shearing lambs markedly increases the risk of
arthritis.
Causes of arthritis
Bacteria enter the body through broken or wet,
softened skin. In WA, Erysipelothrix rhusiopathiae
bacteria are most commonly responsible for
arthritis in sheep, causing the disease called
erysipelas. E. rhusiopathiae bacteria can survive in
soil, faeces and water for varying periods, but the
main source of infection for lambs is probably their
own mothers, who may carry the organism with no
ill effect in the tonsils and pharynx.
In addition to E. rhusiopathiae, other organisms
occasionally cause arthritis, including the bacteria
Histophilus ovis, Escherichia coli and some
Streptococci and Staphylococci. Chlamydia psittaci
— an organism which is neither a virus nor a
bacterium — may also cause arthritis. It is not
possible to identify the specific organism solely
from the appearance of arthritic sheep.
Lambs are most likely to become infected:
 at or soon after birth. Infection may enter via
the umbilical cord, especially in wet pasture
 at marking (ear marking, tailing, castration)
 at mulesing when the lamb’s mother licks the
wound. (Mulesing increases the risk of arthritis
by seven times.)
 at shearing via cuts. (Shearing lambs
increases the risk of arthritis by four times.)
 when held in yards after shearing or after
mulesing
 at other times when the skin is broken or wet
e.g. dog bites and dipping.
Swollen, painful hock joints due to erysipelas
infection.
Signs of arthritis



swelling of usually two or more limb joints,
including the elbow, front knee (or carpus),
stifle (the true knee, in the hind leg) and hock
joints
lameness, with reluctance to walk and
increased time spent lying down. Usually more
than one joint is affected, so sheep will often
walk with a short-stepping, shuffling gait and
hunched back
weight loss because of pain, reduced appetite
and reduced mobility.
Animal welfare
Although some sheep will recover spontaneously,
a small proportion will remain chronically lame and
in poor condition. These animals should be
humanely destroyed.
Important disclaimer
The Chief Executive Officer of the Department of Agriculture and Food and the State of Western Australia
accept no liability whatsoever by reason of negligence or otherwise arising from use
or release of this information or any part of it.
How a vet can help
Always consult a veterinarian when sheep are
lame, as there are numerous causes of arthritis
and of lameness in sheep, including some exotic
diseases, such as foot-and-mouth disease.
A veterinarian will provide the correct diagnosis
and advise on the appropriate treatment. Early
diagnosis and treatment can prevent deaths, and
reduce losses due to condemnation of limbs or
whole carcasses at slaughter.
How to treat arthritis
Once the cause of the arthritis is established,
appropriate treatment can be given. A veterinarian
may prescribe an effective antibiotic.
If sheep are severely lame and emaciated,
recovery will be unlikely. These animals should be
humanely destroyed.
If an outbreak of arthritis first occurs in recently
mulesed lambs, it may be difficult to treat any
immediately without causing further pain and
distress to the lambs. Usually, many will recover
spontaneously in 7–10 days without treatment, but
it is important to assess the group frequently and
initiate treatment as soon as possible, to minimise
the number of chronically affected lambs.
How to prevent arthritis
To prevent outbreaks of arthritis, if possible
eliminate or minimise the predisposing conditions
listed in the Causes of arthritis section above.
Not shearing or mulesing lambs will markedly
reduce their risk of developing erysipelas arthritis.
When marking or mulesing lambs, disinfect
equipment as frequently as possible and do not do
this work in wet or muddy conditions.
If arthritis continues to be a significant problem
despite taking all possible preventive measures,
and a veterinarian has identified the condition
as erysipelas arthritis, then consider vaccinating
ewes.
Erysipelas vaccine is not available in combination
with other commonly used sheep vaccines so will
be an additional vaccination. Ewes need to be
vaccinated twice initially with at least 4 weeks
between doses, and then once every year. Give
the second, or in subsequent years the single
vaccination, to the ewe about 4 weeks before
lambing starts. Vaccinating ewes before lambing
will protect the lamb for the first 8 weeks of life,
covering the time of marking/mulesing.
Swollen ‘knees’ (carpal joints) due to
erysipelas infection.
Do not vaccinate lambs at the same time as
mulesing or marking as it is unlikely to prevent
infection being acquired on that same day. It is
also against the product label directions.
Call a vet when sheep are lame as it could
be an exotic disease
Arthritis of sheep can resemble numerous other
diseases that cause lameness, most importantly
the exotic diseases foot-and-mouth disease and
bluetongue. It can also resemble footrot, foot
abscess, laminitis due to grain overload, scabby
mouth affecting the lower legs, strawberry footrot,
rickets, and white muscle disease due to selenium
or vitamin E deficiency. Even grass seeds, caltrop
or doublegee, can cause lameness in lambs,
which can resemble arthritis at first.
The Significant Disease Investigation Program,
through the Department of Agriculture and Food,
Western Australia and Animal Health Australia
provides subsidised veterinary investigations for
any livestock disease with high stock losses or
similar disease signs to an exotic or reportable
disease. Laboratory testing will often be free of
charge. Search ‘SDI’ at agric.wa.gov.au for more
information on this program.
Producers play a vital role in the early detection of
exotic diseases in Australia. If you see:
 unusual disease signs
 abnormal behaviour
 unexpected deaths
in your stock, ring your local veterinarian, DAFWA
veterinary officer or the Emergency Animal
Disease hotline on 1800 675 888.
Copyright © Western Australian Agriculture Authority, 2013
Copies of this document are available in alternative formats upon request.
3 Baron-Hay Court South Perth WA 6151 Tel: (08) 9368 3342 Email: [email protected]
Website: agric.wa.gov.au
Table 1. Other diseases that arthritis can resemble
Disease
Comments
Bluetongue disease
(exotic to Australia)

Bluetongue typically affects the lips, tongue and gums of sheep,
but lameness also often occurs due to inflammation of the skin just
above the hooves of one or more feet. Many live export trading
partners restrict entry of stock from countries with bluetongue
disease. Although Australia has an effective surveillance program
for bluetongue virus, it is important to have a veterinarian
investigate any signs in sheep that look like bluetongue disease.
DAFWA and Animal Health Australia (AHA) will subsidise the cost
of this investigation through the National Significant Disease
Investigation Program. Ask your veterinarian for more details.
Foot-and-mouth disease (FMD)
(exotic to Australia)

Early detection of a case of FMD will be critical in reducing its
impact on the Australian economy. In sheep, the only easily seen
sign of FMD infection may be lameness. If you have sheep that are
lame or that have sores on their mouth or feet, contact a
veterinarian to investigate the cause. DAFWA and AHA will
subsidise the cost of this investigation through the National
Significant Disease Investigation Program. Ask your veterinarian
for more details.
Footrot

This infection begins in the skin between the claws and may
progress to underrunning the soles and walls of the hoofs.
Lameness may vary from very mild to severe. Footrot is a
reportable disease in WA.
Foot abscess

Usually affects one or two feet. There is a painful swelling just
above the hoof and a pussy discharge.
Laminitis due to lactic acidosis

The feeding history – of excessive or too rapid introduction to grain
or pellets – and clinical examination will help to distinguish
lameness due to laminitis (painful feet) from that due to arthritis
(painful joints).
Scabby mouth affecting the
lower legs

Identifying and controlling scabby mouth is important where sheep
are being sold for live export as some markets reject sheep with
scabby mouth. Scabby mouth can be prevented by vaccination.
Discuss a suitable vaccination program with your exporter and
veterinarian.
Strawberry footrot

This is an infection of the lower limbs by the same bacteria
(Dermatophilus congolensis) that more commonly causes lumpy
wool or dermo. The skin is covered with firmly attached scabs.
Rickets

This disease results from a calcium-phosphorus dietary imbalance
and sometimes from inadequate sunlight. Veterinary investigation
will be necessary to establish a diagnosis.
Selenium or vitamin E
deficiency (white muscle
disease)

The sheep walk stiffly, often with a hunched back and may be
reluctant to stand. The problem is due to muscle damage, not joint
infection.
Grass seeds, caltrop or
doublegee

These may lodge between the digits or pierce the soles of young
lambs, causing lameness. Easily diagnosed.
.
Important disclaimer
The Chief Executive Officer of the Department of Agriculture and Food and the State of Western Australia
accept no liability whatsoever by reason of negligence or otherwise arising from use
or release of this information or any part of it.