More research has emerged suggesting that growth promoters used in the cattle-feeding business may persist in the environment longer than previously thought.
Researchers at Indiana University’s Bloomington School of Public and Environmental Affairs found that while the synthetic testosterone known as trenbolone acetate or TBA breaks down in sunlight, darkness allows it to revert back to a 17-alpha-trenbolone compound.
“This means that, instead of permanent removal in sunlight, the compound would be expected to persist in stream environments, returning to its earlier form overnight in the dark, shallow stream bed where stream water mixes with groundwater, known as the hyporheic zone,” they say in a release.
“These compounds have the potential to disrupt entire ecosystems by altering reproductive cycles in many species, including fish,” said Adam Ward, lead author of the study and a professor at the school. “We expect impacts that extend through the aquatic food web.”
Other compounds could also behave in similar fashion, leaving Ward and his co-authors questioning if regulators are looking at the long-term impacts as they govern the use and approval of such products.
“The next step is thinking about unexpected reactions that occur in the environment and how we can manage the diverse group of potential products and their joint effect on the environment and human health,” said Ward.
In Manitoba, and across the country, TBA is regulated by Health Canada, which said it regularly reviews the quality and efficacy of approved veterinary products.
In an emailed response to questions, the federal department said that “as part of the Chemicals Management Plan, Health Canada is currently prioritizing certain regulated products under the Food and Drugs Act to identify those that may pose significant harm to human health or to the environment. TBA is included in this list of substances being prioritized.”
The impact of the hormone on aquatic life is part of that prioritization, the email concluded. Health Canada did not, however, specifically refer to the University of Indiana study.
Melinda German, general manager of the Manitoba Beef Producers, said the findings of the study don’t worry her.
“I can appreciate the study and what they’re looking at, but for me it’s not a concern,” she said. “What they’ve found is under very specific conditions, it was a laboratory experiment, it wasn’t done in nature… and we know nature doesn’t work under these very precise conditions, so interesting, but it’s not of concern to me at this time.”
Recent advertising campaigns, like those of restaurant chain A&W, have promoted their beef as being hormone free, capitalizing on consumer concerns that the use of hormones is unhealthy and unsustainable.
But German doesn’t think studies like this will give those against the use of hormones fresh ammunition, noting that producer organizations are expanding into areas of consumer outreach.
“There is a lot of information out there, and there is a lot of information the consumer can access, and I think that’s the role of a provincial association like ours, and with our national counterparts, to make sure that we put information out there as well, to talk about is this a big issue for us and how does this impact the industry,” she said. “Right now, based on the findings and the methodology of this study, it’s not something that causes us any concern.”
Dr. Wayne Tomlinson, an extension veterinarian with Manitoba Agriculture, Food and Rural Development, said because Manitoba doesn’t have a large feedlot industry, hormones like TBA aren’t likely prevalent in Manitoba beef production.
“They’re used extensively in feedlots, and we don’t have a large feedlot component, we’re mostly a cow-calf-type province,” he said. “In the cow-calf industry, I would say they are not extensively used.”
The U.S. Environmental Protection Agency said in a 2012 report that more than 90 per cent of beef cattle raised in the United States receive at least one growth implant, and the vast majority of these implants contains trenbolone acetate (TBA). It was reporting the findings of a University of California study that made similar findings.
Companies aren’t required to disclose their product sales and use isn’t tracked through other means, so statistics on TBA use don’t exist.
“It’s a small proportion of the producers that are using it I would say, but we don’t know the numbers because for the companies that sell it, that’s proprietary information. Those companies don’t want to share with government how many doses they’re selling per year,” Tomlinson said, adding that manure from any cattle should be properly spread, away from riparian areas and waterways.
German agreed, and said the use of growth promotants can actually lessen the impact that beef production has on the environment because more meat is produced with fewer resources.
“What the science does show, is that the use of these types of products actually has a beneficial impact back to the environment in terms of water usage, greenhouse gas, and those types of environmental impacts,” said the general manager.
Tomlinson added that increased feed efficiency also reduces the amount of forage that needs to be produced.
In beef production, hormones are usually implanted into an animal’s ear. From there they release hormone from 90 to 160 days, depending on the type of implant. Costs range from $2 to $15 per head.
A spokesman for Manitoba’s minister of water stewardship said that the province regularly tests groundwater and rivers for pollutants, but that “testing of rivers such as the Red and Assiniboine has rarely detected any levels of potential endocrine disrupters such as estrone and 17-beta-estradiol.”
The European Union banned hormone-treated beef in 1989, and hormones have been at the centre of multiple trade disputes since that time. In Canada, hormones have been used since the 1950s.
“They’re a useful tool, I don’t think they’re a dangerous tool,” said Tomlinson. “If they’re not spreading the manure near riparian areas, waterways, this should be a very, very minimal risk to the environment.”