18 September, 2015rodster385Comments (0)

1 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 of
caprine diseases continues to develop in the United States, chlamydia
as well as other organisms may be identified as causes of arthritis in