Arthritis in sheep is an inflammation of the joints of the legs, resulting in loss of production, loss of carcass value and deaths. The main cause of arthritis in sheep is when bacteria enter the body via broken skin. The common times when a lamb will be susceptible to arthritis in this way are: 1) at or soon after birth with infection through the umbilical cord; 2) during docking, castration, and ear tagging; 3) through shearing wounds; and 4) other wounds. There are several bacteria that may be implicated in arthritis. The most common is Erysipelothix rhusiopathiae. Signs appear 2 to 14 days after infection. Affected joints become swollen, hot, and painful, resulting in the lamb becomnig reluctant to move. For most types of arthritis, the only treatment is a course of massive doses of antibiotics. Prevention is the result of good sanitation and hygiene.