ENDECTOCIDAL EFFICACIES OF DORAMECTIN IN NATURALLY PARASITIZED PIGS

The studies reported here were conducted to investigate the effectiven ess of doramectin, given intramuscularly at the rate of 300 mu gkg(-1) of bodyweight, in the treatment of naturally acquired porcine nematod osis and acariasis. Twenty pigs demonstrated to be naturally infected with pulmonary and gastrointestinal nematodes were used in one control study, and 22 pigs demonstrated to be naturally parasitized with Sarc optes scabiei var. suis were used in a second study. In both studies, animals were evenly divided between doramectin plus vehicle and vehicl e-treated groups by restricted randomization. In the anthelmintic stud y, all pigs were necropsied for parasite collection on post-treatment Days 14 and 15. The acaricidal evaluation study was 28 days in duratio n after treatment, with mite population quantifications on the day of treatment and on post-treatment Days 7, 14, 21 and 28. Doramectin prov ed 100% effective in the removal of Metastrongylus salmi, M. elongatus , M. pudendotectus, Strongyloides ransomi, Ascaris suum and Oesophagos tomum dentatum. Levels of Hyostrongylus rubidus. Ascarops strongylina and Macracanthorhynchus hirudinaceus, as observed at necropsy in the d oramectin-treated pigs, were reduced by 99.2%, 99.5% and 62.1%, respec tively, as compared with levels seen in the control pigs. In regard to Sarcoptes scabiei var. suis, no live mites were recovered from dorame ctin-treated pigs during the 7-28 day post-treatment period. In conclu sion, doramectin proved highly effective in the treatment of naturally acquired porcine nematodosis and Sarcoptes scabiei var. suis infestat ion. In addition, all treatments were safe and well tolerated, with no adverse reactions noted in any trial animals. (C) 1997 Elsevier Scien ce B.V.