Livestock health
Suppurative arthritis in sheep
Nancy Ollerenshaw, formerly of
DPI&F
Reviewed by Geoff Knights,
DPI&F
Key points
- Suppurative arthritis is a bacterial disease that has been responsible for large numbers of lamb mortalities.
- Above-average autumn and winter rainfall followed by humid spring conditions causes an increase in the incidence of suppurative arthritis.
- Prevention can be achieved by improving hygiene, using portable yards at marking, not holding lambs for long periods on soil contaminated with manure and delaying marking and mulesing until lambs are out of the spring danger period.
Cause
There are several types of bacteria that have been implicated in causing the arthritis including Pasteurella, Streptococci, Fusobacterium, Corynebacterium, Chlamydia, Staphylococci and Erysipelas. Fusobacterium necrophorum was the organism identified as the cause of the disease in the Cunnamulla district. This organism cannot penetrate the skin, but infects through the navel (umbilical cord) and open wounds following marking and mulesing. The bacterium is naturally found in the intestine, passes out in the faeces and can survive in the soil of contaminated yards for up to ten weeks.
Signs
The signs occur approximately two to three weeks following infection and include lameness and swollen, inflamed joints (shoulder, elbow and hock) that develop into pus-filled abscesses. A high proportion of affected lambs die but those that survive are usually crippled with permanent lameness and fall victim to predators, mismothering and starvation.
Risk factors
Research has shown that above-average autumn and winter rainfall followed by humid, spring conditions is closely associated with an increased incidence of suppurative arthritis. The disease commonly occurs on black soil floodplains that have heavier soils, retain moisture for longer and support higher stocking rates. Properties that are lamb marking during the months of August, September and October are most at risk, especially if they have a past history of the disease. Other high risk factors are a few affected lambs evident in the mob and the use of old yards. Flies are also thought to increase the risk of infection as they irritate the wounds, delaying healing and may contribute to spread of the bacteria.
Treatment
Suppurative arthritis can be treated with antibiotics but not all cases will respond successfully. Treatment is usually only economically justified with highly valued stud animals rather than whole flocks. An effective vaccine has not yet been developed.
Prevention and control
There are several strategies that can reduce the severity of the disease. Employing a high standard of hygiene at lamb marking (ie regular disinfection of instruments and dropping lambs onto a raised platform on their feet) can help prevent the spread of the bacteria. Other practices include the use of portable yards for marking and avoiding holding marked lambs in large concentrated mobs for long periods on soil contaminated with manure (release lambs onto freshly spelled paddocks on red soil if possible).
If seasonal conditions are favourable for the organism to thrive and you have suffered losses in the past, delay your marking/mulesing operation until the lambs are out of the spring danger period. Some properties have even justified changing joining time to avoid a spring lamb marking.
Further information
For further information contact the DPI&F Business Information Centre on 13 25 23 (Queensland residents) or (07) 3404 6999 (non-Queensland residents) between 8 am and 6 pm weekdays, or e-mail callweb@dpi.qld.gov.au.
This DPI&F Note is also published on the DPI&F's PrimeNotes CD-ROM.
Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries and Fisheries Queensland has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.
File No: SW0086 . Date created: October 1997 . Reviewed: February 2005