Thursday, December 18, 2014

Zactran® Eliminates Footrot

Gamithromycin (Zactran®) is macrolide antibiotic licensed for cattle in the treatment and control of bovine respiratory disease. It is not approved for sheep (or goats); however, it may be prescribed by a veterinary for extra-label use.

Foot rot is caused by the anaerobic bacterium Dichelobacter nodosus. D. nodosus does not survive for long in the environment, so the main reservoir of infection is in the animals. In theory, foot rot can be eliminated from a flock, through a combination of vaccination and/or antibacterial treatment (parenteral or topical) and/or culling of infected animals, coupled with good biosecurity.

In a German flock with a high prevalence of foot rot, 184 sheep were given the standard dose of Zactran® (6 mg/kg). The injection was given subcutaneously in the axilla. On day 23, 19 sheep were re-treated with Zactran®. On day 45, no lame sheep or positive lesion scores were observed.

In a Danish study, 48 flocks comprising around 9000 sheep were given the standard dose of Zactran®, subcutaneously on the side of the neck. Of the 48 participating flocks, 44 remained free of foot rot and D. nodosus more than one year later

The results from both studies showed that whole-flock, systemic antibiotic treatment can eliminate foot rot and D.  nodosus. In the Danish study, a single treatment with gamithromycin was sufficient. In the German flock, two treatments at an interval of 22 days were required to eliminate foot rot in some sheep.

Source:  Short Communication, Veterinary Record, January 2014

No comments: