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Ractopamine and Other Growth-Promoting Compounds in Beef Cattle Operations: Fate and Transport in Feedlot Pens and
J K Challis1, S Sura2, J Cantin1,3
1Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada.
Environmental Science & Technology
|January 15, 2021
Summary
Ractopamine (RAC) is found in higher concentrations in cattle feedlots than trenbolone acetate (TBA) or melengesterol acetate (MGA). RAC persists in pen floors, posing contamination risks and requiring improved manure management.
Area of Science:
- Environmental Chemistry
- Agricultural Science
- Animal Science
Background:
- Cattle feedlots utilize various compounds, including trenbolone acetate (TBA), melengesterol acetate (MGA), and ractopamine (RAC).
- Understanding the environmental fate and occurrence of these compounds is crucial for assessing ecological risks and developing management strategies.
Purpose of the Study:
- To investigate the occurrence and environmental fate of TBA, MGA, and RAC in cattle feedlot environments.
- To quantify residues in feces, pen floor material, and simulated rainfall runoff.
- To assess the potential for environmental contamination and inform manure management practices.
Main Methods:
- Conducted two 8-month cattle feeding trials.
- Collected samples of fresh feces, pen floor material, and simulated rainfall runoff.
- Measured concentrations of TBA, MGA, and RAC using analytical techniques.
Main Results:
- RAC concentrations were 3-4 orders of magnitude higher than TBA and MGA in feedlot samples.
- RAC demonstrated persistence in pen floor material, with a half-life of 18-49 days.
- Simulated runoff indicated potential for significant RAC mobilization during rainfall events, with gram quantities transferable.
Conclusions:
- This study is the first to report on the occurrence and fate of RAC in cattle feedlot environments.
- RAC poses a significant contamination risk due to its high concentrations and persistence.
- Findings underscore the need for effective manure management practices to mitigate environmental risks associated with RAC.
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