NAVLE Musculoskeletal

Ovine and Caprine Arthritis Study Guide

November 14, 2026 25 min read
Arthritis in small ruminants represents a significant economic and welfare concern, causing lameness, decreased productivity, and chronic suffering.

Overview and Clinical Importance

Arthritis in small ruminants represents a significant economic and welfare concern, causing lameness, decreased productivity, and chronic suffering. Joint disease in sheep and goats can be broadly categorized as infectious (septic) arthritis or non-infectious (degenerative) arthritis. Understanding the etiology, clinical presentation, diagnosis, and treatment of these conditions is essential for NAVLE success.

Key infectious causes include bacterial agents such as Erysipelothrix rhusiopathiae, Chlamydia pecorum, and various Mycoplasma species, as well as viral causes, particularly the small ruminant lentiviruses (SRLVs) including Caprine Arthritis Encephalitis Virus (CAEV) in goats and Ovine Progressive Pneumonia/Maedi-Visna Virus in sheep.

Category Causes Species Affected
Viral CAEV (Caprine Arthritis Encephalitis) OPP/Maedi-Visna Virus Goats (primarily) Sheep (primarily)
Bacterial - Septic Erysipelothrix rhusiopathiae Streptococcus dysgalactiae Trueperella pyogenes E. coli, Staphylococci Both sheep and goats, especially neonates
Chlamydial Chlamydia pecorum Primarily feedlot lambs (1-8 months)
Mycoplasmal M. agalactiae M. capricolum subsp. capricolum M. mycoides subsp. capri Both, more severe in goats
Degenerative Osteoarthritis Traumatic arthritis Both, older animals

Classification of Arthritis in Small Ruminants

High-YieldOn NAVLE, remember that CAEV and OPP are now grouped as Small Ruminant Lentiviruses (SRLVs). Cross-species transmission can occur, especially when sheep and goats are housed together.
Syndrome Age Affected Clinical Signs
Polyarthritis Adults more than 6 months (most common) Bilateral carpal swelling ('Big Knee'); Progressive lameness; May walk on knees; Weight loss; Poor hair coat
Encephalomyelitis Kids 2-6 months Progressive paresis, ataxia; Proprioceptive deficits (hindlimbs first); Hypertonia; Paralysis; Often fatal
Indurative Mastitis Adult does at parturition 'Hard udder' syndrome; Firm, swollen mammary gland; Agalactia; Decreased milk production
Interstitial Pneumonia Adults Progressive dyspnea; Chronic respiratory compromise; Weight loss

Viral Arthritis: Small Ruminant Lentiviruses

Caprine Arthritis Encephalitis (CAE)

Caprine Arthritis Encephalitis Virus (CAEV) is a lentivirus in the family Retroviridae causing chronic, progressive disease in goats. CAEV has a seroprevalence of 38-81% in dairy goats in North America and Europe. The virus persists lifelong within monocytes and macrophages, evading host immune responses.

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