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ORIGIN: United States

Extension Goat Handbook

This material was contributed from collections at the National Agricultural
Library. However, users should direct all inquires about the contents to
authors or originating agencies.

DOCN 000000069
NO G-15
AU D. M. Sherman; U. of Minnesota, St. Paul
RV S. B. Guss; Pennsylvania State U., University Park
DE Health and Disease Management

The limb joints of animals are designed for mobility. In conjunction with the muscles and tendons, the joints allow for flexion and extension of the legs and permit a wide range of motion and activity. Normal joint function is essential for good health, particularly in grazing animals such as goats which may have to cover large areas over varying terrain in search of food. Normal joint function also allows flight from predators and is important for breeding success in active bucks. In addition, lameness or swellings over joints may reduce an animal's chances in the show ring.

2. Normal limb joints are comprised of several structures. First are the bone ends, covered with cartilage and shaped to interlock for increased stability. The cartilage is quite smooth, for reducing friction and wear in the joint. A space exists between the cartilage surfaces called the joint cavity. This space is filled with joint (or synovial) fluid which lubricates the joint and acts as a shock absorber to reduce the trauma associated with movement. The fluid is held in place by a fibrous joint capsule which is lined with a synovial membrane that produces the joint fluid. Outside the joint capsule are numerous ligaments, muscles and tendons which add further strength and stability to the joint. The tendons are also surrounded by sheaths containing fluid known as bursae. Inflammation of the tendon sheaths is known as bursitis. Inflammation of the joint from any cause is known as arthritis. Any or all of the structures comprising the joint may be damaged in arthritic conditions.

3. Recognizing Joint Disease
Arthritis may result from a variety of infectious and noninfectious causes. A single joint may be affected or multiple joints involved (polyarthritis). Depending on the cause, signs of arthritis may vary. For example, in bacterial or traumatic arthritis, the affected joint may be swollen and warm to the touch. In early viral or nutritional arthritis, no visible change may be detected in the joint. In these cases, the presence of arthritis is suggested by observation of signs such as reluctance or difficulty in rising, slowed return to the barn at milking time, inability of bucks to mount does at breeding time, limping or uneven gait, or complete disuse of a single limb. Even when these signs are noted, other conditions which might result in abnormal motion should be considered. These would include fractures, laminitis or founder, foot rot, and white muscle disease (vitamin E/selenium deficiency). In addition, various neurological problems may be misinterpreted as musculoskeletal disease.

4. Several diagnostic procedures may be employed to identify the cause of arthritis. Examination of the joint fluid obtained by aseptically tapping the joint may be useful. Large numbers of neutrophils in the fluid are suggestive of bacterial arthritis. Large numbers of mononuclear cells are more indicative of viral arthritis. Little change in the fluid composition may be observed in traumatic or nutritional arthritis. In the case of bacterial arthritis, joint fluid may be cultured to identify the causative organism and to select the appropriate antibiotic therapy.

5. In cases of nutritional or traumatic arthritis, radiographs may be helpful in establishing a diagnosis and prognosis for recovery. Serological testing may be required for the diagnosis of arthritis due to virus or mycoplasma. Successful treatment of individual cases of arthritis and control and prevention of additional cases depends on accurate and specific diagnosis.

6. Specific Causes of Caprine Arthritis Bacterial Arthritis -- Lacerations or puncture wounds over joints can lead to bacterial infection. Injuries such as these should be cared for immediately. The affected area should be cared for immediately. The affected area should be cleaned thoroughly with soap and water. If the joint has been opened, suturing may be indicated. Antibiotic therapy should be initiated to prevent infection.

7. In young kids, bacterial polyarthritis can occur. The organisms involved are usually E. coli, Corynebacterium pyogenes, or staphylococci. The condition is recognized by lameness and swelling in one or more joints, particularly the front knees (carpi), hocks and stifles. This condition is secondary to bacterial infection elsewhere in the body, usually the navel or digestive tract. The bacteria are carried to the joints via the bloodstream. Therapy is often ineffective and prevention is the preferred method of control. Unclean environment and improper kid care promote the incidence of polyarthritis. Improved management practices will reduce the occurrence of this disease. Maternity pens should be used for kidding, and kept clean and dry with bedding changed between births. Navels of newborns should be dipped in iodine immediately after birth. Kids should receive adequate colostrum within six hours after kidding. They should be housed in warm, dry quarters, and not overcrowded.

8. Mycoplasma Arthritis -- Mycoplasmas are small microorganisms which differ from bacteria in that they do not have a cell wall. They are difficult to culture in the laboratory and much confusion exits with regard to the species of mycoplasma responsible for caprine arthritis in the United States. Several species of goat mycoplasmas are known in the US but Mycoplasma mycoides subspecies mycoides, large colony type, appears to be most responsible for cases of mycoplasmal arthritis. The prevalence and distribution of caprine mycoplasma arthritis is unclear, and sporadic reports from several regions of the US have appeared in the veterinary literature, most notably from California.

9. Mycoplasma infection produces a severe systematic disease in which arthritis may be the only sign or may be accompanied by high fevers, inappetence, pneumonia, diarrhea, keratoconjunctivitis (pink eye), or sudden death. All animals in a herd may be affected, but the more dramatic signs are seen in kids and younger adults. Outbreaks are often preceded by some stress such as dehorning. The infection may be carried unnoticed in a herd for extended periods.

10. Whenever several animals in a group are suddenly affected with arthritis along with signs of illness elsewhere in the body, mycoplasma should be suspected. Any dead animals should be submitted to a diagnostic laboratory for specific diagnosis. Blood samples from living animals should also be taken for evaluation of titers to mycoplasma infection. Correct diagnosis is important since few antibiotics are effective against mycoplasma. Tylosin and tetracyclines may be useful in controlling herd outbreaks although losses may be high.

11. Viral Arthritis -- (CAE) A recently discovered retrovirus has been identified as a cause of chronic arthritis in goats. It is very likely that many previously unexplained cases of caprine arthritis were the result of this slow virus infection. The caprine arthritis encaphalitis virus (CAEV) was first recognized as a cause of progressive paralysis in two of four month old kids resulting from infection of the brain (encephalitis). Later it was demonstrated that the same virus also produces a progressive chronic arthritis in older goats. The presence of this virus in the US goat production is believed to be very high.

12. Nutritional Arthritis -- One specific syndrome of arthritis related to feeding deserves mention. It involves the excessive consumption of calcium in the ration by mature bucks. Lactating does and young growing animals may require supplemental calcium in the diet. However, mature bucks fed in similar ration are likely to develop arthritis due to excessive deposition of calcium in the bone (osteopetrosis). Proliferative calcification (osteophytes) forming on the margin of joints disrupts normal joint architecture and may impair mobility and breeding effectiveness. Osteophytes may be visible radiographically. To prevent this problem, mature bucks should be fed either grass hay or not more than two pounds of alfalfa hay daily.

13. Traumatic Arthritis -- Because goats are prone to fighting, traumatic joint injuries (sprains, dislocations, torn ligaments) are not uncommon. Sudden lameness and swelling of a single joint without fever is suggestive of traumatic injury. Affected goats should be isolated and confined with exercise restricted. The joint may be wrapped with an elastic bandage and cold compresses applied to minimize swelling. The animal may be placed on aspirin to reduce pain and inflammation. The degree of recovery is dependent on the extent of the injury.

14. Other Causes of Arthritis -- Herd outbreaks of polyarthritis in lambs due to Chlamydia sp., a virus-like organism, are known to occur in the United States. It has been suggested that chlamydial arthritis in goats also occurs, especially in herds which have experienced outbreaks of chlamydial abortion. As interest in and recognition ofcaprine diseases continues to develop in the United States, chlamydia as well as other organisms may be identified as causes of arthritis in goats.

ORIGIN;United States


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