Toxicity of calciferol,warfarin and their combinations to Rattus norvegicus (albino) and R. rattus

The response of Rattus norvegicus and R. rattus to calciferol, warfarin and a combination of these compounds was tested. Both species succumbed to the recommended bait concentrations of calciferol (1000 mg/kg) and warfarin (250 mg/kg) when tested individually. However, R. rattus was more susceptible to lower concentrations of calciferol (500 and 750 mg/kg) as compared to R. norvegicus, which was sensitive to lower concentrations of warfarin (12.5 and 25 mg/kg bait). Addition of calciferol at different concentrations did not affect the toxicity of warfarin against R. norvegicus. However, with R. rattus calciferol (250–350 mg/kg) or warfarin (50 mg/kg bait), which individually produced partial mortality, in combination produced a complete kill besides accelerating death. Combination of higher dosages of calciferol with warfarin (1000 + 250 mg/kg bait) tested against both species showed no advantages, resulting in neither lower bait consumption nor speedier death, though individually the components gave complete kills.