HERD HEALTH
PIH-36
pork
industry
handbook
COOPERATIVE EXTENSION SERVICE • PURDUE UNIVERSITY • WEST LAFAYETTE, INDIANA
Swine Arthritis
Authors
Richard Ross, Iowa State University
James Bailey, South Dakota State University
Reviewers
Dave Huinker, Ames, Iowa
James Leafstedt, Alcester, South Dakota
Arthritis is commonly recognized as being a major factor in swine lameness. The disease is brought about by infection of the joint and the surrounding tissues by bacteria or mycoplasmas. U.S.D.A. meat inspection records indicate that trimming of parts of swine carcasses and discarding of whole carcasses due to arthritis are leading causes of loss at slaughter. Greater loss probably occurs on the farm because of slower and less efficient gains and reduced performance by adult breeding stock and lactating sows. Death loss occurs in some instances but is not generally considered to be a major factor.

Other factors in lameness in swine include those related to nutritional imbalances or deficiencies, foot and leg lesions resulting from trauma and improper conformation, and degenerative bone and joint changes.

Streptococcal Arthritis
Streptococci cause acute and chronic arthritis in 1-3-week-old pigs. Aside from the diarrheal and respiratory diseases, streptococcosis is probably one of the most common diseases affecting young pigs.

The streptococci are classified serologically according to the Lancefield system. Representatives from virtually every one of the 19 Lancefield types have been isolated from swine; however, most isolates from naturally occurring arthritis have been either the Lancefield Group C organism known as Streptococcus equisimilis or unnamed strains belonging to Group L.
Streptococcal infection occurs under many types of management and environmental conditions. The organisms are common in vaginal secretions, respiratory
tract secretions and sow milk. They may invade the baby pig's body by way of the navel, foot or skin wounds or the tonsils. Rough flooring or bedding material causes abrasions of the legs of nursing pigs that undoubtedly facilitate invasion by these organisms.

Streptococcal arthritis never affects a large percentage of pigs; the morbidity rate is usually less than 5%. Ten to 20% of affected pigs may die, either as a result of systemic lesions produced during the septicemic stage of the disease or of causes related to impaired mobility (starvation, overlaying, etc.).

Clinical Signs
Acute streptococcal infection is characterized by a fever, roughened hair coat, depression and lameness. As the disease progresses, the affected pig may lose weight and have marked enlargement of the affected joints. One or several joints may be involved; swelling is most often observed in the knee, elbow and hock joints. The pain associated with the condition and the resulting impairment of movement restrict the ability of affected pigs to nurse. Affected pigs are often stunted and have chronic arthritis for life.

Tissue Changes
Affected joints contain increased amounts of cloudy joint fluid with clots of fibrin. There is swelling, discoloration and redness of the membranes. The connective tissue capsule around the joint is thickened and may contain small abscesses. As the disease becomes chronic there may be damage to the articular cartilage. Lesions are also observed in the growth plates of the bones.
Cooperative Extension Work in Agriculture and Home Economics, State of Indiana, Purdue University and U. S. Department of Agriculture Cooperating. H. G. Diesslin, Director, West Lafayette, Ind. Issued in furtherance of the Acts of May 8 and June 30, 1914. It is the policy of the Cooperative Extension Service of Purdue University that all persons shall have equal opportunity and access to its programs and facilities without regard to race, religion, color, sex or national origin.