Document Detail

PCDD and PCDF depletion in milk from dairy cows according to the herd metabolic scenario.
MedLine Citation:
PMID:  18462776     Owner:  NLM     Status:  MEDLINE    
High level of PCDD+PCDF contamination in bulk milk (9.7 pg WHO-TE g(-1) fat) from 1604 Holstein Fresian lactacting cows was observed just four weeks after the beginning of their exposure to a feed supplement contaminated at 10.4 ng WHO-TE kg(-1) dry matter. In-farm produced hay and silage showed levels not exceeding 0.2 ng WHO-TE kg(-1) dry matter. After the supplement withdrawal, it was possible to monitor the depletion phase for a following 75-day period in milk, until the levels dropped well below 3.0 pg WHO-TE g(-1) fat, the EU regulatory Maximum Residue Level for PCDD+PCDF. During this phase, the half-life was calculated as 17+/-3 days, on WHO-TEQ basis. The full availability of farm data on both cow nutrition and milk production allowed the calculation of the carry-over rate (COR) (PCDD+PCDF milk excretion vs. feed), which was 46% at the end of the exposure. This COR value is justified from the main TE contribution of Penta-CDD and -CDF congeners (63%), and the half-life is among the shortest of all those described in the literature both for experimental and naturally-exposed dairy cows. A fugacity-based model predicts a bulk milk contamination of 5 pg WHO-TE g(-1) fat, compared to the 10 pg WHO-TE g(-1) fat level observed. Such findings are discussed in light of the lactation and metabolic status of the herd for which the transition period, characterised by a negative metabolic energy balance and a consequent adipose tissue mobilization, could play a relevant role.
Gianfranco Brambilla; Igor Fochi; Michele Falce; Stefania Paola De Filippis; Alessandro Ubaldi; Alessandro di Domenico
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-05-06
Journal Detail:
Title:  Chemosphere     Volume:  73     ISSN:  0045-6535     ISO Abbreviation:  Chemosphere     Publication Date:  2008 Aug 
Date Detail:
Created Date:  2008-08-15     Completed Date:  2008-10-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0320657     Medline TA:  Chemosphere     Country:  England    
Other Details:
Languages:  eng     Pagination:  S216-9     Citation Subset:  IM    
Italian National Institute for Health, Toxicological Chemistry Unit, Viale Regina Elena, 299, I-00161 Rome, Italy.
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MeSH Terms
Animal Feed
Benzofurans / chemistry,  metabolism*
Food Contamination
Linear Models
Milk / metabolism*
Tetrachlorodibenzodioxin / analogs & derivatives*,  chemistry,  metabolism
Time Factors
Reg. No./Substance:
0/Benzofurans; 0/chlorinated dibenzofurans; 0/polychlorodibenzo-4-dioxin; 1746-01-6/Tetrachlorodibenzodioxin

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