Some rodenticidal properties of cholecalciferol against Rattus argentiventer

Y. M. Lam

Abstract

Cholecalciferol was evaluated agairst R. argentiventer in the laboratory. The median lethal dose (LD₅₀) of cholecalciferol against R. argentiventer was 25.53 mg/kg. The mean days to death in rats succumbing to an oral lethal dose were 5.7 days in males and 6.3 days in females. The median lethal feeding period (LFP₅₀) for 0.01% cholecalciferol against R. argentiventer was 3.3 days and LFP₉₉ was 14.7 days. Cholecalciferola t 0.075% elicited 100% mortality in both sexes in l-day no-choice tests. The lowest lethal dose in feeding tests against males was 5.77 mg/kg and the highest dose ingested by a survivor was 49.36 mg/kg. In females, the lowest lethal dose was 4.26 mg/kg and the highest dose survived was 47.02 mg/kg. The mean days to death in rats succumbing to a lethal dose in no-choice feeding tests were 6.3 days in males and 7.0 days in females. Palatability studies (4-day choice feeding tests) indicated that cholecalciferol showed poor palatability against R. argentiventer at all the concentrations tested, giving low mortality for both sexes as a result of poor consumption of the poison baits. Rats were able to detect cholecalciferol at the lowest concentration tested (0.01%). At concentrations higher than 0.025%, there were very poor acceptance (less than 10%) md palatability ratios of 0.11 and less were obtained for cholecalciferol baits.

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