HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Laben, R. C. Articles by Peoples, S. A. Search for Related Content PubMed PubMed Citation Articles by Laben, R. C. Articles by Peoples, S. A.

Lactational Output of DDT Fed Prepartum to Dairy Cattle

Departments of Animal Husbandry, Agricultural Toxicology, and Physiological Sciences, University of California, Davis

ABSTRACT

Dry dairy cows and heifers approaching their first lactation were fed 1,1,1-trichloro-2,2-bis(4'-chlorophenyl) ethane (DDT) from the 90th to the 30th day before expected parturition. A control and three treatment groups of four animals each were used. Feed contamination levels of 30, 300, and 600 ppm were approximated; mean total intakes of crystalline DDT were 28, 250, and 520 g per cow for the treated groups. No gross signs of toxicity were observed. Body fat DDT concentrations rose to 16, 253, and 590 ppm in the treated groups. Concentrations fell after cessation of intake at rates of 8 to 10% per week. Maximum milk fat DDT concentrations after calving were 19, 231, and 812 ppm for the treated groups, respectively, and declined through the lactation at from 9 to 11% per week. The DDT level in the milk fat of the cows with lowest intake did not reach 1 ppm until after 17 to 26 wk of lactation. Therefore, giving dry cows or heifers feed contaminated at or above this level is impractical, even if the feed is withdrawn a month before calving. Whole blood levels of DDT, determined twice during the experiment, were closely associated with body stores of DDT, particularly in the animals fed at the two higher levels of the insecticide.