Residues of organochlorine pesticides in milk gland secretion of cows in perinatal period

The rate of organochlorine pesticide excretion from bovine milk glands was examined during the perinatal and postnatal period. Elevated levels of hexachlorocyclohexane isomers were quantified in the secretion before parturition, as compared with milk and colostrum. The sum of DDE, DDT, and DD concentrations was also markedly higher in the secretion before parturition, as compared with colostrum and milk. The increased concentration of fat-soluble pesticides in milk gland secretion before parturition exerted an adverse effect on the function of the gland.