ISRAEL JOURNAL OF
VETERINARY MEDICINE
Case Report
RADIOLOGICAL AND BACTERIAL FINDINGS IN A CASE OF SEVER
FOOTROT
Goshen T., Steinman A. and Bargai U.
Koret School of Veterinary Medicine, Hebrew University, Jerusalem
Summary
A feedlot calf was presented with severe, unresponsive footrot. The calf
died the morning after presentation, and two weeks after the infection was
first diagnosed by the owner. The severity of the infection was
demonstrated by radiography. The failure of antibiotic therapy, the rapid
progression of the infection and the severe lesions demonstrated by
radiography suggest that this is a case of severe footrot. Based on
previous clinical experience of treating unresponsive cases of footrot, the
authors suggest considering the use of tilmicosin in similar cases.
Introduction
Footrot (also known as interdigital phlegmon, foul in the foot, necrobacillosis
and pododermatitis) is a major cause of lameness in beef and dairy cattle.
The disease occurs in all seasons, but tends to be most prevalent during wet
seasons and under wet conditions. The clinical findings include edema and
erythema of the interdigital region, necrotic tissue in the interdigital space and
a fetid odor. Lameness is severe, body temperature is elevated, and milk yield
decreases. Fusobacterium necrophorum with other secondary gram-negative
anaerobes are considered as the etiologic agents . Beta-lactam antibiotics
and tetracyclines are the drugs of choice but other antibiotics and procedures
such as foot baths, applying a protective dressing and surgical excision were
also described . In the beginning of the 1990s, two reports of a severe form of
footrot in the United Kingdom were published. This report describes a case of
severe footrot in a calf in Israel, which is the first report to our knowledge of
this form outside the United Kingdom. The bacteriological and radiological
findings are also described.
Case details
History
An eight months old Israeli Holstein bull calf was presented with severe
lameness in March 2004 in a feedlot. The feedlot contained 800 calves,
mainly Holstein and mixed-breed beef calves. The calves were separated by
age, breed and size, and kept in groups of 25 calves on average (range = 10
to 50).
The lame calf was treated by the owner with procaine penicillin (pen-30®;
Vitameax Holland (20000 IU/kg bwt i.m. sid) for 5 days without clinical
improvement. The calf was then presented to the attending veterinarian who
diagnosed footrot (interdigital phlegmon) and treated the calf with
oxytetracycline (Alamycine®: Norbruck Ireland (10 mg/kg bwt i.m. sid) for 6
days. However, this treatment was also ineffective and the leg became more
swollen and painful.
Clinical examination
The calf was examined by the senior author (T.G.) two weeks after the
lameness was first detected by the owner. Clinical examination revealed
severe lameness (4/5), the claws were separated and the tissues above the
coronary band were inflamed, swollen and red (Fig 1). Pus and blood were
draining from several sinuses. Septic arthritis was suspected, and amputation
was considered. Unfortunately the calf died the next day. The affected leg
was then removed and radiographs were taken (Figures 2, 3).
Radiological findings:
Figure 2. Antero-posterior radiograph of the right hind leg
The soft tissue dorsal to the coronary band was much enlarged and highly
radio-opaque (a). This indicated wide-spread phlegmon and cellulites of the
region There were gas foci in the phlegmon tissue (b) which indicated the
presence of gas-forming organisms in the tissue. The sepsis has already
reached the periosteum, which was evident by periosteal proliferation (c).
Figure 3. Latero-medial oblique radiograph of the right hind leg
The distal phalangeal joints of both lateral and medial digits. The bones in
these joints were in congruity and the joint space was not enlarged (d)This
indicated that these joints were not yet infected by the infectious process
which was extending distally from the soft tissue above the coronary band.
The interphalangeal joints (e) were infected and there was an ongoing
process of septic arthritis in both joints. In the lateral interphalangeal joint the
distal portion of PII was completely destroyed and the general structure of the
joint was lost. In the medial digit, the interphalangeal joint space was much
enlarged which is a radiological sign of arthritis. Both PI and PII were infected
and osteomyelitis was present in both bones.
Bacteriological findings
Fusobacterium necrophorus was isolated from samples of soft tissue.
Fig 2.
Fig 3.
Discussion
Interdigital phlegmon is a common cause of lameness in Israeli dairies and
feedlots. As the disease is usually cured by penicillin or other beta-lactam
therapy, the diagnosis is usually based on the clinical signs and response to
antibiotic therapy. In this case, the unsuccessful outcome might be the result
of a late diagnosis of the lameness by the owner. This assumption is further
supported by the profound damage of the soft tissues and the joints which
was detected. The radiological findings showing the profound damage to the
soft tissues and bones are similar to the sequelae of untreated interdigital
phlegmon. However, in recent years cases of severe footrot, a form of
interdigital phlegmon that is unresponsive to standard antibiotic therapy, were
seen in Israel. This form of the disease is sporadic and usually results in
culling of the affected animals. Due to its rapid development, the lack of
response to treatment and the fatal outcome, it is possible that this case was
also a case of severe footrot. As the causative organism Fusobacterium
necrophorum may become resistant to penicillin, interdigital phlegmon cases
which do not respond to therapy should be treated surgically or with other
antibiotics. The author (T.G.) and other colleagues from the Hachaklait have
treated successfully several unresponsive cases of foot rot with Tilmicosin
(Micotil®, Elanco 10 mg/kg bwt IM twice, 3 days apart). Tilmicosin is a semisynthetic macrolide antibiotic approved for veterinary use in non-lactating
cattle, sheep and swine. Tilmicosin is also approved for treatment of
respiratory diseases associated with Pasteurella spp., Manhemia haemolitica,
Mycoplasma spp. and Actinobacillus pleuropneumoniae. The efficacy of
tilmicosin for treatment of mastitis in heifers and dry cows was also tested.
The use of macrolids for treatment of severe footrot was reported with various
degrees of success.
In conclusion, the use of tilmicosin in severe cases of foot rot, which were not
improved by standard antibiotic therapy, should be considered. Furthermore,
tilmicosin has a long withdrawal period before slaughter and is not registered
for use in lactating cows which limits its use to non-lactating cattle.
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