In vivo efficacy of 81.723 hfu, a new pleuromutilin derivative against experimentally induced airsacculitis in chicks and turkey poults.

The efficacy of the pleuromutilin derivative 81.723 hfu was tested in chicks and turkey poults by experimentally infecting them with Mycoplasma gallisepticum. The data were treated to obtain the mean effective doses, and these were compared to those obtained with tylosin tartrate. The compounds were administered either by ingluvial catheter or via the drinking water. Therapy was started on the day of inoculation or 7 days thereafter, respectively. The experiments showed that the compound 81.723 hfu was significantly more active in chickens than tylosin tartrate by both methods of administration of drinking water. In turkey poults the pleuromutilin derivative and tylosin tartrate had comparable activity.