Foot Rot and Foot Scald in Goats & Sheep

UNP-0087, New February 2007, Maria Lenira Leite-Browning, DVM, MS, Extension Animal Scientist, Alabama A&M University

Introduction

Foot Rot

Foot rot is a contagious disease of the hooves in goats and sheep. This disease is prevalent in the southern region of the United States. The South's wet and humid climate makes it conducive for foot rot and foot scald. Foot rot is primarily caused by the microorganisms Dichelobacter nodosus and Fusobacterium necrophorum. Dichelobacter nodosus can be found in contaminated soil.

Foot Scald

Foot scald, also referred to as benign foot rot or interdigital dermatitis, is an inflammation between the toes caused by F. necrophorum. Persistent moisture on the skin between the toes can increase susceptibility to foot scald. However, foot scald does not seem to be contagious. A significant proportion of the herd will likely show signs of the disease under ideal environmental conditions. Foot scald often precedes hoof rot.

Foot scald and foot rot outbreaks occur most often during persistent rainy weather along with high temperatures, when animals walk across wet pastures and muddy soil. If not treated, these animals can become permanently infected. During the rainy season, infected animals can contaminate the soil, which can increase disease transmission to other animals. Overgrown hooves will also predispose an animal to foot scald or rot. The disease causes stress to the animals and can affect weight gain, reproductive rates, and wool production. Foot rot and scald may incur additional costs for treatment and increased labor during an outbreak.

Introducing an infected animal into a non-contaminated herd can create herd contamination. Foot rot microorganisms can also be carried to soil on visitors' boots. Keep visitors out of pastures or request them to wear disposable or rubber boots when walking through pastures. This is a biosecurity measure that can help minimize farm-to-farm transfer of D. nodosus and F. necrophorum. Reports indicate that direct transmission of foot rot can occur between cattle, sheep, and goats that are in/share the same pastures.

Research has shown that genetic makeup helps determine whether an animal is resistant or susceptible to these hoof problems. Among sheep, the Merino breed is more susceptible, and the Gulf Coast breeds are more resistant. Boer goats are more susceptible, and the Spanish and Kiko breeds are more resistant to foot rot and foot scald.

Diagnosis, Treatment, and Prevention

Diagnosis

The first signs of hoof rot or scald are limping, holding limbs above the ground, grazing on knees, and reluctance to walk. Foot scald is characterized by interdigital inflammation. The skin between the toes is pink to white in color, raw, moist, and very sensitive to the touch. Foot rot can be mild or severe. The erosion of tissue between the sole of the toe and the hard outer hoof characterizes foot rot. Upon trimming the hoof, the outer shell of the hoof will be separated from the inner sole. Severe cases of foot rot may be accompanied by the presence of pus and a foul smell. Animals with severe foot rot might show fever, loss of appetite, with hoof deformity. Animals with chronic infections show a loss of body condition and decreased production, resulting in an unhealthy animal overall. Although foot rot and foot scald are common in small ruminants, they should also be inspected for other foot diseases or injury.

Goat limping as a sign of foot rot

Treatment

• Isolate affected animals for treatment and trim hooves. Inspect for signs of rot or scald and rule out other possible causes of lameness.
• Treat the feet with a solution of 10 percent copper sulfate or zinc sulfate. Several products are commercially available. Use of 7 percent iodine on the feet is also effective.
• When a substantial number of animals in a herd are affected, the use of a footbath may be the best treatment option. Animals must stand in a zinc or copper sulfate solution to allow absorption into the hoof wall. Another option for whole-herd treatment is the use of absorptive pads saturated with the zinc or copper sulfate solution. The pad should be placed in a high traffic area that goats and sheep must pass through, such as a gate, lane, or water trough. When animals stand to drink at the water, hooves will be treated. Lameness is generally resolved within a couple of days after treatment.
• Antibiotic therapy, such as injections of long-acting penicillin or oxytetracycline, is effective.
• Keep treated animals in a dry environment for 24 hours after treatment. Hooves should be trimmed as needed to expose the infected tissue to oxygen.
• Maintain clean pens and barns.

Foot rot microorganisms can remain in the soil for several weeks. After animals have been treated, they should be transported to a clean pasture or pen that has not been exposed to infected animals.

Prevention

• Cull highly susceptible animals and enhance selective breeding for resistance to foot rot.
• Trim hooves regularly. Trimming prevents hoof overgrowth, which creates an environment for foot rot.
• Quarantine animals for several weeks after they arrive.
• Check animals for foot lesions before purchasing.
• Give animals a footbath upon returning from shows or after purchasing, and prior to their re-entry into the herd.
• Vaccinate sheep as a preventive tool for foot rot. A vaccine for foot rot in sheep is available. The Food and Drug Administration does not approve this vaccine for use in goats.

References

Browning, R. Jr., Payton, T., Donnelly, B., Leite-Browning, M. L., Pandya, P., Hendrixson, W. & Byards, M. (2006). Evaluation of three meat goat breeds for doe fitness and reproductive performance in the southeastern United States. 8th World Congress on Genetics Applied to Livestock Production, Belo Horizonte, MG, Brazil.

Depiazzi, L. J., Richards, R. B., Henderson, J., Rood, J. I., Palmer, M., & Penhale, W. J. (1991). Characterisation of virulent and benign strains of Bacteroides nodosus. Veterinary Microbiology, 26(1-2), 151-160.

Egerton, J. R., Ghimire, S. C., Dhungyel, O. P., Shrestha, H. K., Joshi, H. D., Joshi, B. R., et al. (2002). Eradication of virulent foot rot from sheep and goats in an endemic area of Nepal and an evaluation of specific vaccination. The Veterinary Record, 151(10), 290-295.

Every, D. (1982). Proteinase isoenzyme patterns of Bacteroides nodosus: Distinction between ovine virulent isolates, ovine benign isolates and bovine isolates. Journal of General Microbiology, 128(4), 809-812.

Ghimire, S. C., Egerton, J. R., Dhungyel, O. P., & Joshi, H. D. (1998). Identification and characterisation of serogroup M among Nepalese isolates of Dichelobacter nodosus, the transmitting agent of foot rot in small ruminants. Veterinary Microbiology, 62(3):217-233.

Ghimire, S. C., Egerton, J. R., & Dhungyel, O. P. (1999). Transmission of virulent foot rot between sheep and goats. Australian Veterinary Journal, 77(7):450-453.

Pugh, D.G. (2003). Diseases of the foot. Sheep and Goat Medicine. Ed. Saunders, 225-227.

Wani, S. A. & Samanta, I. (2006). Current understanding of the aetiology and laboratory diagnosis of foot rot. Veterinary Journal, 171(3):421-428, Review.

Whittington, R. J. (1995). Observations on the indirect transmission of virulent ovine foot rot in sheep yards and its spread in sheep on unimproved pasture. Australian Veterinary Journal, 72(4):132-134.

For more information, contact your county Extension office. Visit http://www.aces.edu/counties or look in your telephone directory under your county's name to find contact information. Issued in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and June 30, 1914, and other related acts, in cooperation with the U.S. Department of Agriculture. The Alabama Cooperative Extension System (Alabama A&M University and Auburn University) offers educational programs, materials, and equal opportunity employment to all people without regard to race, color, national origin, religion, sex, age, veteran status, or disability.