Contagious ovine digital dermatitis (CODD) is a severe foot condition of sheep first described in 1997. The condition is caused by a spirochaete resembling those involved in digital dermatitis in cattle which has led to the adoption of the current name. The condition in sheep may have originated from dairy cattle where digital dermatitis is a major cause of lameness. Sheep with CODD show severe lameness typically affecting one digit of one foot. There is reduced grazing activity with long periods spend lying down. There is rapid loss of body condition.
The characteristic clinical picture of CODD is a primary lesion at the coronary band of the outer wall with subsequent invasion and under-running of the hoof wall from the coronary band towards the toe causing detachment then shedding of the horn capsule. However, it proves difficult to differentiate CODD from footrot in many situations and veterinary investigation is essential to ensure correct treatment. In some cases, the damage to the corium may be so severe that re-growth of the horn is permanently affected. Typically, there is also loss of hair extending 2-3 cm above the coronary band. There is no interdigital skin involvement.
Lame sheep must be examined immediately. Affected sheep should be treated with parenteral long-acting oxytetracycline (10 mg/kg) and a NSAID, and skin lesions treated topically with oxytetracycline aerosol. Other antibiotics such as long-acting amoxicillin have been used successfully. There is anecdotal evidence that tilmicosin and gamithromycin injection may be more effective than oxytetracycline and amoxycillin. Further published data on comparative treatment regimens are needed before authoritative advice can be given.
There is some evidence that whole group antibiotic injection may reduce the appearance of new cases of CODD in the group but this practice is contrary to RUMA guidelines on the responsible use of antibiotics which are specific in their advice on the administration of antibiotics to prevent disease: Fluoroquinolones, 3rd and 4th generation cephalosporins and long acting macrolides (tilmicosin and gamithromycin) have an important place in the therapeutic armoury for serious diseases of both animals and humans. The use of these classes in both human and veterinary medicine has produced particular debate and the following guidelines for use should be followed.
Fluoroquinolones, 3rd and 4th generation cephalosporins and long acting macrolides should only be used therapeutically not for prophylaxis.
Strict biosecurity is essential to prevent introducing CODD onto the farm. All purchased sheep must be quarantined for at least one month and all cases of sudden severe lameness investigated. It would be prudent to keep sheep separate from cattle if digital dermatitis is present in the cattle.
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