Arthritis in sheep

What is arthritis in sheep?

Arthritis is most likely to occur in young lambs, especially after marking, mulesing, or shearing.

Arthritis in sheep is caused by a variety of bacteria, most of which are common environmental organisms found on the skin, in faeces, and in soil. These bacteria enter the bloodstream through cuts or wounds and lodge in joints, causing inflammation.

There are three main types of arthritis in lambs:

• Suppurative arthritis
• Erysipelas arthritis
• Chlamydial polyarthritis

When to watch for it

Arthritis is most likely to occur in young lambs, especially after marking, mulesing, or shearing. Looking at the description of each type of arthritis in Clinical Signs below, watch for:

• Suppurative arthritis: 2–7 days after birth or marking.
• Erysipelas arthritis: 10–14 days after marking/mulesing, chronic form around 6 months.
• Chlamydial arthritis: 3–6 months of age.

Risk increases significantly with:

• Mulesing (7× higher risk).
• Shearing (4× higher risk).

Clinical signs

Common signs of arthritis in lambs include:

• Lameness and visible swelling in two or more leg joints.
• Fever, stiffness, reluctance to move.
• Cloudy joint fluid (sometimes without swelling).
• Chronic cases show thickened joints and persistent lameness.

Diagnosis requires postmortem and lab culture of joint samples.

These are signs in each type of arthritis:

Suppurative arthritis

Typically occurs two to seven days after birth if the infection starts in the umbilicus or following marking/mulesing. The shoulder, elbow, knee stifle and hock joints are the joints usually infected. Bacteria commonly involved with suppurative arthritis include streptococcus, staphylococcus, actinomyces pyogenes and fusobacterium necrophorum.

Erysipelas arthritis

Caused by the bacterium Erysipelothrix rhusiopathiae. The acute form of erysipelas arthritis typically occurs 10-14 days after marking or mulesing. Initially there is fever and severe joint pain but no obvious heat or swelling. Some lambs will recover from the acute form, but many will progress to the chronic form, which is typically seen in lambs around six months of age. Affected lambs will have thick, swollen joints that contain a large amount of cloudy fluid. With erysipelas arthritis, any joint may be affected but it is usually the elbow, hock and stifle joints.

Chlamydial polyarthritis

Caused by the bacterium Chlamydophilia pecorum and typically affects lambs 3-6 months of age. Affected lambs initially will have a fever, become stiff and lame and may be reluctant to move. Affected joints typically contain cloudy fluid but are not always swollen. It is important to note that Chlamydia pecorum infections can also cause abortion in your ewes.

How to manage

Preventing arthritis involves minimising bacterial contamination and promoting wound healing:

• Minimise faecal contamination by lambing into a well-grassed paddock.
• Use high hygiene standards at lamb marking; avoid wet or dusty conditions and fly-prone times.
• Use clean instruments and change disinfectant regularly.
• Minimise handling for 3–4 weeks post-marking/mulesing.
• Prevent fly irritation and keep lambs dry.
• Avoid dipping off-shears or during high grass seed infestation.
• Ensure dipping fluids are changed regularly and contain antiseptic.

How to treat

Antibiotics can be effective if administered early. Success depends on the stage of infection. 

How to prevent

Vaccination is available for Erysipelas arthritis only:

• Administered to ewes before lambing.
• Immunity passed via colostrum.
• Protects lambs for 6–8 weeks.
• Does not protect against Suppurative or Chlamydial arthritis.