Medycyna Wet. 67 (11), 715-719, 2011

full text

Olechnowicz J., Jaśkowski J.M
Lameness in small ruminants
The main causes of lameness in sheep include foot rot (FR), interdigital dermatitis (ID), and contagious ovine digital dermatitis (CODD). FR is a bacterial disease caused by Dichelobacter nodosus. An infection by faecal bacterium Fusobacterium necrophorum may develop as a result of injuries to the interdigital skin occurring over a prolonged period in a wet environment. FR is highly contagious and can be transmitted from sheep to sheep via pasture, bedding or handling pens; however, this disease can also be spread by sheep that do not show any clinical indications of the disease. In the case of ID infection, only the presence of Dichelobacter nodosus causes lameness. In most cases of CODD infection, Treponema vincentii has been isolated. The mean prevalence of lameness was around 8 - 10%, varied between years and depended on the climate and the standard of hygienic conditions. The main causes of lameness in goats were cracks and erosion on the horn of the bulbs of the heel that extended along the internal side of the axial hoof wall. Similarly as in sheep, Dichelobacter nodosus and Fusobacterium necrophorum were isolated from foot lesions. The clinical diagnosis was ID. The mean prevalence of lameness in goats ranged from 9% to 15%. The common detection of Fusobacterium necrophorum together with Dichelobacter nodosus supports the hypothesis that FR results from a synergistic interaction between these two organisms. Risk factors associated with infection and lameness in small ruminants are as follows: the wet season and moisture, smudge of dirt with mud of dens for animals, concentration of animals, virulence of the bacteria present, and the frequency of routine foot trimming. Particularly in sheep, an increased frequency of foot trimming is associated with an increased prevalence of FR. Lameness in small ruminants may also be related to an abnormal conformation of limbs or to lesions of the skin and udder. A highly reliable method for the evaluation of locomotion in small ruminants is the scoring scale using scores from 0 to 6. The treatment of infected animals consists primarily of their separation from the flock and the application of an antibacterial therapy, in which almost any topical antibiotic and foot spray can be effective. During transmission periods it is advisable to bathe animals’ feet in zinc sulphate (10 or 15%) or formalin (3%) every five days. Supplemental dietary biotin at 5.25 mg/day healed hoof lesions within 7 months. An improved locomotion of sheep was visible within 4 months. Vaccination plays a valuable role, but it is not fully effective, and immunity is of relatively short duration. Vaccination should be repeated at six-month intervals. Prevention and control of the two most common causes of lameness in small ruminants (foot rot and digital dermatitis) that eliminate Dichelobcter nodosus and Fusobacterium necrophorum are more feasible given the climate and environment can lead to minimization of lameness, improvement of animal welfare and increased productivity.
Keywords: small ruminants, lameness, foot rot, interdigital dermatitis, contagious ovine digital dermatitis, treatment