Abstract
Iophenoxic acid (IA) is a compound that causes an increase in the plasma and serum iodine concentration of animals that ingest it, and was evaluated as a marker for assessing bait acceptance by stoats and weasels. The baseline plasma or serum iodine concentration was measured in 12 captive and 10 wild stoats, and one captive weasel. Iophenoxic acid was mixed into broken hen eggs in amounts of 1, 2, 4, or 5 mg per egg (5 mg equals 0.01% in a 50 g egg), and the eggs were then fed to the captive animals. The mean plasma or serum iodine concentration in the dosed stoats was significantly higher than the mean baseline concentration (3.3 μg/100 ml) after 7 days (309.5 μg/100 ml) and after 14 days (24.0 ng/100 ml), but not after 21 days (6.4 μg/100 ml). The duration of plasma or serum marking in stoats (c. 2 weeks) was not as long as reported in most other studies of eutherian mammals (most more than 8 weeks). Not enough data were collected to determine the duration of marking in weasels.