Health Management, Diseases, and Parasites - Goat Science and Production - page 223

by the submission of samples (blood and testicles) to a
diagnostic laboratory.

Many other joints may be infected. Joint fl uid is often dark,
yellowish, thick, or cloudy. Diagnosis depends on anti-
body determination, virus isolation, or histology. The juve-
nile form is limited to kids 2-4 months of age. Kids begin
to lose neurologic control of their back legs, and as the
disease ascends, eventually the back legs are paralyzed.
Infection is mainly transmitted from doe to kid via
colostrum and milk. Many serologically positive goats
never show clinical signs of the disease. These goats are
subclinical carriers of the disease. Other than palliative
treatment for degenerative arthritis, there is no treatment
and no vaccine for this disease. Prevention is the key and
it depends on early identifi cation of infected goats by
repeated serological testing and culling these animals from
the herd. Raising kids with known seronegative mothers is
another option. This disease is not a major problem in meat
goat herds or fi ber goat herds since the disease is mainly
spread only from mother to her offspring. In dairy goat
herds where milk is pooled and fed to multiple kids, an
entire kid crop can be infected by one doe. Dairy goat
producers routinely pasteurize milk prior to using it to feed
kids to prevent transmission of this and other milk-borne
diseases.

Lameness
Lameness means to move with pain or diffi culty. Lameness
in goats is usually associated with the foot and is usually
the result of owners failing to perform regular foot trim-
ming. The main infectious causes of lameness involving
the foot are contagious foot rot caused by Fusobacterium
necrophorum and Dichelobacter nodosus , interdigital der-
matitis (foot scald) caused by Fusobacterium necropho-
rum , and foot abscesses caused by Arcanobacterium
pyogenes , F. necrophorum , and others.
Contagious foot rot is a major problem of goats. The
causative agent, D. nodosus , is specifi cally adapted to the
horny layer of the hoof, which it invades and underruns.
D. nodusus is a contagious bacterial agent that lives only
on the feet of infected sheep and goats. It survives for only
short periods of time on pastures. In wet, warm weather,
infection can spread rapidly throughout a herd. It can cause
extreme lameness depending on the strain (virulence) and
the degree of underrunning of the hoof wall. Treatment
requires paring away the unattached hoof wall and soaking
feet in zinc sulphate, formalin, or copper sulfate. Sodium
lauryl sulphate is added to these disinfectants to increase
penetration into the hoof. Antibiotics may be useful. Strict
isolation is necessary to prevent further spread. There are
vaccines but they are of short duration and have limited
effects. They are used to reduce prevalence to the point
where eradication can be attempted.
Interdigital dermatitis (scald) is similar to foot rot,
although it is not contagious, and is caused only by F.
necrophorum , which is an environmental bacteria and does
not cause destruction of the hoof wall. Treatment is much
easier, and if goats can be placed in a dry area and their
feet soaked, the disease is usually easily cured.
Foot abscesses can be a sequel to interdigital dermatitis/
foot rot or penetration of the hoof wall or sole by foreign
bodies. In severe cases, it can result in infection of the inter-
phalangeal joint (the coffi n joint). Severe lameness results
and can last for months. Prolonged antibiotic treatment and
rest in confi nement may assist recovery. If infection of the
distal interphalangeal joint occurs, then amputation of the
affected claw may be the most practical treatment.
Caprine arthritis encephalitis (CAE) infects goats world-
wide. It is present in an adult form and a juvenile form.
The adult form is the most common and causes lameness
associated with arthritis of joints but can also involve the
udder (hard bag) and the lungs (lungers). The front knees
(carpal joints) especially become thickened and painful.

Abnormalities of the Mammary Gland
The most common cause of swelling of the mammary
gland is mastitis, which is infl ammation of the secretary
tissue of the mammary gland usually caused by a bacterial
infection. Udder swelling (CAE “hard bag”) can also be
caused by viral infection, by physical trauma, and by the
development of severe edema of the gland (periparturient
edema). Theilitis is infl ammation of the teat and may be
caused by bacterial infections, viral infections (contagious
ecthyma), chemical irritants, thermal burns, and trauma.
Mastitis is mostly a problem in dairy goats and is caused
by contagious organisms that are spread from goat to goat
in the milking parlor. The most common organisms are
Staphylococcus epidermidis , Staphylococcus aureus , and
Streptococcus agalactia . Any bacteria, fungus, or yeast
that inadvertently gains access to the mammary gland can
cause mastitis. Occasional cases are caused by E. coli ,
Klebsiella , Paseurella sp. , Candida , Nocardia , and others.
Infections are classifi ed as peracute (gangrenous), acute,
subclinical, and chronic. The major cost of mastitis is the
loss of secretory tissue, which reduces milk production and
subsequently kid growth. Most cases of acute mastitis
cause the doe to become febrile and decrease feed intake.
The affected gland becomes red, hot, swollen, and painful.
The milk may be watery or contain fl akes and clumps.
Treatment with systemic or intramammary antibacterials