The effect of even or uneven applications of DDT prills to pasture on ddt residues in stock

摘要

Abstract DDT residues were measured in the omental fat of sheep and in the milk of cows grazed on pastures that had been topdressed either evenly or unevenly with DDT prills but at the same average rate of DDT/acre. The currently recommended withholding periods were observed between the treatment of pasture with DDT prills and the first grazing by sheep and dairy cows. The residues found in sheep fat or in milk fat from stock on the areas treated unevenly were similar to those in stock grazed on the uniformly topdressed areas, which suggests that the pattern of grazing was random rather than selective on the unevenly treated areas. These results are discussed in relation to farm topdressing machinery and to the problem of insecticide residues in animal fats.