Studies on rodenticides (III) : Feeding preference of Norway rats for warfarin baits and lethal effects of the baits

Abstract

Feeding preference and lethal dosage of Norway rats on warfarin baits were studied in laboratory. The accumulated lethal dosage with 5 day successive feeding of warfarin baits were 3.13-8.00mg/kg and the lethal dosage with one day feeding was 264mg/kg. The feeding preference on 0.03% and 0.1% warfarin baits was equal to non-poisonous bait. This means that their avoidance of warfarin dry baits is not shown, if the concentration is as low as 0.1% or 0.03%. Days necessary to kill the rats by successive feeding of warfarin baits were 3 to 8 days from the initial feeding, independent of the total dose consumed, if the concentration is in the range of 0.03% to 0.1%.