Objective: This study was carried out to determine whether spirochaetes are frequently associated with (P) DD in Iran’s dairy cattle and to find out the best way for control and treatment of the disease.
Design: Clinical field study.
Animals: Four dairy herds with a prevalence rate of more than 30% of lameness due to (P) DD.
Procedure: All individual cows in the herds were received the treatment by spraying of lincomycine Hcl solution directly on their feet twice daily for one week. In each farm prior to treatment and at the end of trail the cows were observed individually to assess the lameness score. Tissue samples were also taken from the hoof skin of 1-5% of the affected cows for lustier histopathological and immunohistochemistry studies.
Statistical analysis: Paired student “t” test.
Results: Based on the clinical observations, this method of therapy was more effective in the treatment and control of the disease. In the H&E staining there was microscopic signs of loss of epidermal barrier, acanthosis, hyperkeratosis, parakeratosis, ulcer of dermal papillae, increased of mitotic rate in the basal layer and dermatitis with microabscesses. The histopathological examination of lesions using silver stain showed, huge numbers of unidentified spirochetae-like organisms. In the immunocytochemical staining .spirochetaes in the skin biopsies were identified by polyclonal antisera to l-9-I85MED and 2- 1498 American Isolated Treponemes.
Conclusion: It was concluded that spray solution of lincomycine Hcl improved lameness score in cattle with (P) DD. This treatment policy was effective for treatment and may be useful for the control of the disease. According to the results, spirochete is frequently associated with, (P) DD and may be responsible for, pathological changes in digital dermatitis cases in dairy cows in Iran. I. Far. Vet. Med Univ. Tehran. 57, 1: 71-77, 2002.
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