Hormones Q&A Session


On July 28, 2020, CAST hosted a webinar over the new release, Impacts on Human Health and Safety of Naturally Occurring and Supplemental Hormones in Food Animals. In a discussion afterwards, the panelists answered questions from the viewers. The panelists included: Robert Collier, Laura Hernandez, Jimena Laporta, Jim Lauderdale, and Zachary Smith. Below are some of the questions and answers–if you would like to view all of them, you can find the full Q&A session here.

How often have impact assessments found significant hormone release into the environment? What has been the most serious case recognized so far? 

ZS: Post-approval environmental impact studies are conducted by many institutes. Initial environmental assessment studies are conducted prior to approval of the technology. If there is significant hormone release to the environment, the technology would not be approved for use in the first place. Since wildlife would produce naturally occurring hormones, special surveillance interest for synthetic hormones seems logical. Additionally, steroid hormone metabolism changes the isomer of the hormone from the anabolic β subunit form, to the α subunit that is not anabolic. 

JL: Extensive environmental impact assessments (EA) are required for each product approval by the Center for Veterinary Medicine (CVM) of the Food and Drug Administration (FDA). If a significant negative impact due to hormone release into the environment was identified during the extensive environmental assessment studies, that potential product would not be granted regulatory approval for sale/use. Therefore, no serious cases exist of a negative environmental impact due to hormone release associated with an environmental assessment. 

Can someone provide links to official confirmations of those statements–the assays and the levels detected/eliciting of biological effects in humans? 

JL: 1) Safety evaluation standards in the United States, TM Farber, M Arcos, and L Crawford, in Anabolics in Animal Production, Public health aspects, analytical methods, and regulation, pp. 509-514, in Symposium held at OIE, Paris, 15-17 February 1983, Office International des Epizooties, ISBN 92-9044-118-6. 

2) Guidance for Industry #3, General Principals for evaluating the safety of compounds used in food-producing animals, Food and Drug Administration, Center for Veterinary Medicine. 

3) Freedom of Information (FOI) for each hormone product of interest. 

Are there surveys that have queried the extent of use of hormonal supplements among livestock producers? For example, is aggregate use 100% of producers (assuming non certified organic producers) or is it a much smaller percentage.  These types of data are used in the pesticide “business” to understand better probabilistic population level exposures. 

ZS: At least for steroid hormone use in finishing cattle, ~90% of steers and heifers are administered a steroidal implant. This information is released periodically by APHIS of the USDA in a survey of feedlot producers. From my experience, implant technology is not as widely used in calf-hood situations (cow-calf producer) as it has been in the past. I believe it has something to do with perceived increases in calf value when the technology is not used. Survey of sale barn prices by Dr. Ken Odde at KSU would suggest that non implanted calves do not receive a premium when sold. 

JL: For reproduction products, the percentage use is on the order of 10% to 20% for beef and on the order of 50% for dairy. Since these products are used to assist with breeding, and since breeding cattle are not intended for harvest associated with breeding, the percentage of cattle receiving reproduction related hormones at harvest is essentially zero. 

Does increasing the use of exogenous hormones contribute to increase in cost of production? 

RC: The return on investment for use of exogenous hormones is typically at least 3/1 or greater ($3 return for every dollar invested). This more than covers the additional cost of production. Producers do not use products that are not profitable to them. 

Given the impact of COVID-19 on the food system, are practices being modified? What are the impacts on production goals, etc.? 

ZS: At least for beta adrenergic agonist, the COVID-19 pandemic has made using these technologies more difficult, from the standpoint of logistic issues related to feeding for the prescribed amount of time and getting cattle harvested in a timely manner. Many folks who could not get a confirmed harvest date for cattle opted out of using a beta-adrenergic agonist. For the steroid hormones, our recommendation when the harvest plants were shutting down was to re-implant if one could handle the cattle and had the available labor resources. Estrogen containing implant delay fattening by influencing long bone growth, plus implants can really be influential on dry matter feed conversion. In any case, the COVID-19 pandemic might have increased adoption of late phase implanting in order to not have cattle go through a time of no implant payout. It is important to realize that steroidal implants have not withdrawal period, so this practice was acceptable. 

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