Footrot - Cattle

Also know as: Foul in the foot — Infectious Pododermatitis — Interdigital Necrobacillosis — Interdigital Phlegmon — Hoof Rot — Foot Rot

Introduction

Foot rot in cattle is caused by the anaerobic bacteria Fusobacterium necrophorum. Fusobacterium necrophorum is ubiquitous in the environment of cattle as it is a normal inhabitant of the intestine and faeces. <Kanoe, M., Imagawa, H., Toda, M (1975) Distribution of Fusobacterium necrophorum in bovine alimentary tracts. Bulletin of the Faculty of Agriculture, Yamaguti University, Japan, 26:161-172.</ref> It can also remain dormant in the soil for several months. The organism contaminates areas where cattle congregate.

Foot rot in cattle should not be confused with foot rot in sheep. The two diseases are different and cross infection between the two species is not believed to occur. Foot rot in sheep requires not only a virulent strain of Dichelobacter nodosus to be present, but also Fusobacterium necrophorum.

Distribution

Foot rot has been reported from many countries. The disease is particularly prevalent in temperate climates with a moderate rainfall and relatively high cattle population density.

Most cases of foot rot result from the organisms entering the subcutaneous tissue through interdigital skin, likely as the result of traumatic damage or the action of noxious agents in slurry. Commensal organisms of the skin may also play a role.

Signalment

Any breed, age or sex of cattle can be affected.

Clinical Signs

Once F. necrophorum has entered the interdigital space, extensive cellulitis develops. The inflammatory oedema between the claws pushes them apart, stretching the interdigital ligaments and causing considerable pain. The skin between the claws fissures then sloughs. A common complication is septic arthritis of the distal interphalangeal joint.

Signs are usually a sudden onset generalised lameness of varying degree. Animals are usually pyrexic. The affected leg will appear swollen and erythematous and the animal may be noted to be shifting its weight. If chronic, there may also be evidence of disuse atrophy in the affected limb. The animal may have reduced weight gain or weight loss and have a decreased milk yield.

On closer examination of the foot, it will appear hot, moist, erythematous and have a foul odour. There may be skin necrosis and sloughing of the affected area and a purulent discharge may be present. The swelling may have caused the two digits to separate, and the cleft between the claws may appear to be larger than normal.

Diagnosis

Clinical signs plus physical examination of the foot will lead to a presumptive diagnosis of the disease.

Radiography is not useful in most instances, but is essential in cases failing to respond to treatment and when either septic pedal arthritis or a retroarticular abscess is suspected.

The organism can be isolated and cultured in a laboratory, but this is not usually required for diagnosis.

Exclusion of differential diagnoses such as retroarticular abscessed is important. The characteristic of this condition is that swelling occurs around one digit only, which is different to foot rot. Severe diseases such as Foot and Mouth should also be eliminated as this is a notifiable disease.

Treatment

If treated, most cases respond very rapidly, usually with very little after effect. Recurrence will occur occasionally. Natural immunity appears to inhibit reinfection for at least six months.

Suitable antibiotics for treatment of the condition include penicillin G, oxytetracycline, sulfadiazine/trimetroprim, sulfadimethoxine and tylosin. All should be given by injection for three days as topical therapy is not effective. Always follow withdrawal guidelines.

Intravenous infusion via the digital vein with a suitable antibiotic is the most effective way to treat the most advanced cases.

If the skin of the interdigital space has sloughed, topical treatment is also essential. This is particularly important if a secondary lesion appears to be starting in the dorsal region of the interdigital skin. The wound should cleaned with soapy water, then thoroughly dried and a topical dressing such as an antibiotic paste should be applied. The lesion must then be protected for a few days minimum.

Control

Control measures include footbathing of animals with 5% copper sulpahte or formalin. Zinc methionine and paraformaldehyde have also been used.

Proprietary vaccines are available but it is, at present, questionable if they are cost effective. Two injections are required one month apart, but the immunity that develops only reduces the incidence of the disease and does not eliminate the risk completely. Vaccinating bulls twice per year is strongly recommended to maintain breeding performance.

The reduction of slurry is also extremely important. Good drainage around drinking and feeding areas is helpful. The isolation of cows (or the use of a protective boot) during the early infectious stages of the disease is strongly recommended. Very early, adequate treatment is essential.

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References

Blowey, R. W (1994) Interdigital causes of lameness. Proceedings of the 8th Symposium of Disorders of the Ruminant Digit, Banff, Canada, 142-154.

Chirino-Trejo, M., Woodbury. M. R., Huang, F (2003) Antibiotic sensitivity and biochemical characterization of Fusobacterium spp. and Arcanobacterium pyogenes isolated from farmed white-tail deer (Odocoileus virginianus) with necrobacillosis. Journal of Zoo and Wildlife Medicine 34:202-268.

Choquette-Lévy, L., Baril, J., Lévy, M., St-Pierre, H (1985) A study of foot disease of dairy cattle in Quebec. Canadian Veterinary Journal 26(9):278-281; 19.

Eddy, R. G., Scott, C. P (1980) Some observations on the incidence of lameness in dairy cattle in Somerset. Veterinary Record, 106:140-144.

Russell, A. M., Rowlands, G. J., Shaw, S. R., Weaver, A. D (1982) Survey of lameness in British dairy cattle. Veterinary Record, 111:155-160.