Related Experiment Videos
Hexachlorobenzene retention and excretion by dairy cows
Journal of Dairy Science
|March 1, 1976
Summary
Hexachlorobenzene and DDE residues in cow milk fat accumulated similarly over time, with hexachlorobenzene showing a slower initial increase. Post-feeding, both compounds decreased, indicating potential bioaccumulation and elimination dynamics in dairy cows.
Area of Science:
- Environmental Chemistry
- Toxicology
- Animal Science
Background:
- Persistent organic pollutants (POPs) like hexachlorobenzene (HCB) and DDE can accumulate in animal products.
- Understanding residue dynamics in dairy cows is crucial for food safety and risk assessment.
Purpose of the Study:
- To compare the residue accumulation and elimination of hexachlorobenzene (HCB) and a reference compound, DDE, in the milk and body fat of dairy cows.
- To determine the biological half-lives of HCB and DDE in cows.
Main Methods:
- Two groups of three cows each were administered daily doses of 5 or 25 mg of HCB and DDE for 60 days.
- Residue concentrations in milk were measured at 5-day intervals during dosing and for 60 days post-dosing.
- Subcutaneous body fat and milk fat concentrations were analyzed.
Main Results:
- HCB accumulation in milk fat was slower than DDE during the initial feeding period, reaching a 1:1 ratio by day 40.
- Average milk fat concentrations at 40-60 days were 9.0-10.4 ppm (25 mg/day HCB) and 2.1 ppm (5 mg/day HCB).
- Post-feeding, HCB and DDE concentrations in milk fat decreased by 32% and 51% respectively within 15 days, with biological half-lives ranging from 29 to 64 days.
Conclusions:
- HCB and DDE exhibit similar accumulation and elimination patterns in dairy cows, though HCB accumulates more slowly initially.
- The milk fat to body fat ratio suggests differential distribution between fat depots.
- Findings provide insights into the toxicokinetics of these persistent organic pollutants in livestock.