Ringworm is a common fungal skin infection in young cattle and
is a potential zoonosis. Most outbreaks are caused by
Trichophyton verrucosum with Trichophyton
mentagrophytes less common. Dermatophytes will survive for
months in buildings and housed cattle often become infected after
physical contact with contaminated feed barriers, walls etc. Poorly
nourished calves and immune suppressed individuals (e.g. persistent
BVD infection) will be more susceptible to infection.
The greyish lesions are slightly-raised, well-circumscribed,
extending up to 10 cm diameter and may become confluent, and are
more common on the head and neck but may extend over much of the
Ringworm lesions are more common on the head and neck but may
extend over much of the body
Ringworm lesions are greyish and slightly-raised,
well-circumscribed, and extending up to 10 cm diameter but may
become confluent as in this case.
Diagnosis is based upon demonstration of ectothrix spores on
microscopic examination of plucks of hair surroundings the
lesions. Culture of T. verrucosum requires selective
While the disease is often described as self-limiting,
resolution may take four to nine months during which time other in
contact animals become infected with contamination of the animals'
environment and infection of subsequent groups. Topical
enilconazole is used but may not be effective in all outbreaks and
repeat applications are necessary.
The vaccine can be used both for active immunisation to reduce
clinical signs of ringworm caused by Trichophyton
verrucosum (prophylactic dose) and to shorten the recovery
time of infected cattle showing clinical signs of ringworm
Onset of immunity has been demonstrated at 3 weeks after
vaccination. The duration of protection has not been
determined but field reports suggest that after the recommended
course has been completed cattle continue to be protected without
Initially the whole herd should be vaccinated with a course of
two vaccinations, 10-14 days apart. Subsequently, for closed herds
only young calves require revaccination at around 2 weeks of age,
followed by a second injection 10-14 days later. New animals
introduced into the herd should receive a full vaccination course
at the appropriate dosage. No subsequent doses are required.
Vaccination can be used during pregnancy.