Arthritis in Cattle.

ARTHRITIS, while not limited to cattle, has been recognized in this species since the beginning of veterinary history (4). Despite this long-standing recognition and the fact that arthritis presents definite clinical symptoms and lesions of diagnostic, prognostic, and pathological importance, surprisingly few studies delving into the cause and pathology of this important disease process in cattle have been reported. From an economic viewpoint, the livestock industry takes a considerable yearly loss from the effects of arthritis (11). A large number of animals are condemned at slaughter houses each year, the medical attention required for afflicted animals is expensive and afflicted animals have poor performance records. Comparative evaluation of this disease as it occurs in man and animal has already proved valuable, and further investigations along such lines should be worthwhile. Joint lesions which cause arthritis may be divided into two general categories: inflammatory and degenerative (1). The inflammatory type is often proliferative, especially in the later stages. In the earlier stages, exudative signs play the predominant role. The degenerative type of lesion has been designated by a variety of terms such as arthritis deformans, osteoarthritis, chronic articular rheumatism, chronic osteoarthritis, chronic osteoarthrosis, hypertrophic arthritis, degenerative joint disease, and chondromalacia arthrosis. We prefer the term arthrosis or, more fully, arthrosis deformans. The term arthrosis distinguishes the degenerative from the inflammatory type of joint diseases, the etiology and pathogenesis of which are different. Terms ending in "osis" generally describe degenerative processes such as nephrosis, while the ending "itis" should be reserved for truly inflammatory processes such as nephritis. This conforms with the original meaning of the Greek genus "itis". In any study of lesions involving the joints, it is imperative to appreciate the four characteristics of articular cartilage: (1) avascularity, (2) insensitivity, (3) low metabolic rate, and (4) poor reparative ability. The concept of the musculoskeletal system as a structural and functional unit must also be kept in mind when studying and evaluating arthritis. This unity is reflected whenever one of the three major components (bones, joints, and muscles) of the locomotor system becomes abnormal and the other two ultimately undergo secondary changes (10).