Tulathromycin in the Treatment of Respiratory Infections in Sheep

In this study the effectiveness of tulathromycin, a new semi-synthetic macrolide, was assessed in treatment of sheep respiratory infection. The research was carried out on 36 half-breed sheep with clinical signs of bacterial respiratory infection. Specimens of nasal discharge (40-45 mL) from all animals were collected for bacteriological tests, before treatment and 2, 5, 7 and 15 days after the drug injection. Bacteriological investigations showed the presence of gram-negative strains of Mannheima (Pasteurella) haemolytica, P. Multocida, Mycoplasma ovipneumoniae and Pseudomonas spp. The susceptibility of the isolated microorganisms to tulathromycin and other antimicrobials drugs used in veterinary medicine was estimated by in vitro test. A single dose of tulathromycin (DRAXXIN, Pfizer, Milan Italy) (2.5 mg/kg b.w.) was injected subcutaneously in the neck of each sheep. In treated animals, the symptomatology decreased rapidly 2 days after treatment and completely after 5-7 days, with remission and normal functioning of respirator activity. Actually, no literature data are present on tulathromycin treatment in sheep; therefore this research describes the first therapeutic use in this specie.