Identification of Thiocyanate as the Principal Metabolite of Oxamyl in Lactating Goat

The metabolic fate of [1-14C]oxamyl in a lactating goat was investigated. The test animal was administered five consecutive daily doses orally at 31 ppm oxamyl dietary burden. Most of the radioactivity was eliminated via urine (45.3%) and feces (7.2%). [14C]Oxamyl equivalents in edible tissues (liver, kidney, muscle, and fat) and in milk accounted for 6.7 and 10.2% of the dose, respectively. A small percentage (1.9%) of the dose was exhaled as volatile metabolites (primarily 14CO2). No oxamyl nor any closely related metabolites were detected in tissues, milk, or urine. Extensive degradation/metabolism of [1-14C]oxamyl was observed. Radioactive thiocyanate was the major metabolite identified in the milk as well as in the methanol/water extracts for all tissue samples. Oxamyl-derived residues in the urine have been identified as thiocyanate, N-methyloxamic acid, oxamide, and N-methyloxamide. Keywords: Oxamyl; metabolism; goat; thiocyanate