title: Time profile of abamectin and doramectin excretion and degradation in sheep faeces.
abstract: We studied abamectin and doramectin excretion and their degradation in sheep faeces under field conditions on pasture after a single subcutaneous dose (0.2mg/kg body weight). In the excretion experiment, maximal abamectin concentration (1277 ng/g dry faeces) was detected on day 3, while doramectin concentration showed two peaks (2186 and 1780 ng/g dry faeces on days 2 and 5, respectively). Both avermectins were excreted at approximately the same rate (k=0.23 day(-1) for abamectin and 0.19 day(-1) for doramectin). In the field, a rapid loss of abamectin and doramectin from sheep faeces was seen during the first 32 days after which concentrations remained constant at approximately 77 ng/g and 300 ng/g, respectively. The half life values (DT(50)) for abamectin and doramectin dissipation from sheep faeces were 23 and 22 days, respectively, during the first 32 days. Dissipation of both avermectins was strongly correlated with moisture content of the faeces.
authors.affiliation: Institute of Physiology, Pharmacology and Toxicology, Veterinary Faculty, University of Ljubljana, Gerbiceva 60, SI-1000 Ljubljana, Slovenia. lucija.kolar@vf.uni-lj.si <lucija.kolar@vf.uni-lj.si>
authors.forename: Lucija
authors.initials: L
authors.lastname: Kolar
authors.forename: Vesna Cerkvenik
authors.initials: VC
authors.lastname: Flajs
authors.forename: Jernej
authors.initials: J
authors.lastname: Kuzner
authors.forename: Irena
authors.initials: I
authors.lastname: Marc
authors.forename: Milan
authors.initials: M
authors.lastname: Pogacnik
authors.forename: Andrej
authors.initials: A
authors.lastname: Bidovec
authors.forename: Cornelis A M
authors.initials: CA
authors.lastname: van Gestel
authors.forename: Nevenka Kozuh
authors.initials: NK
authors.lastname: Erzen
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000032:analysis* / Q000737:chemistry; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D004350:Drug Residues / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D004787:Environmental Pollution / Q000009:adverse effects; D005243:Feces / Q000737:chemistry*; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D012757:Sheep Diseases / Q000517:prevention & control; D034561:Sheep, Domestic / Q000378:metabolism*; D013995:Time
chemical_list: D000871:Anthelmintics; C048324:abamectin; D007559:Ivermectin; C084101:doramectin