Hot topic in cattle health: GFI #191
Although not commonly used in the Northeast, steroidal implant use in beef cattle is still utilized on many operations nationwide. Addressing some potential changes coming from the FDA at CattleCon ’23 was Brad Johnson, Ph.D., of Texas Tech University.
Johnson delved into the impact of Guidance for Industry (GFI) #191, “Changes to Approved NADAs – New NADAs [new animal drug applications] vs. Category II Supplemental NADAs.” But first he provided some background information.
He noted that the objectives of the cattle feeding industry are growth (fast growth rates, high rates of conversion of feed to muscle and high muscle-to-fat ratio) and product quality (minimal subcutaneous fat and tender product).
Growth-enhancing technologies (GETs) have been used safely and efficiently for about 70 years in the U.S., with benefits to cattle, according to Johnson. GETs increase average daily gain (based on a 2015 study, by 8% – 28%), moderately alter dry matter intake and create improvements in feed efficiency (of 5% – 20%). They are placed in the back of the ear – a spot with a lot of blood flow that’s also a harmless spot in regards to food safety. There are over 30 commercially available steroidal implants with anabolic activity in the U.S.
So why didn’t the average producer hear about GFI #191? Because the parties involved (the pharmaceutical companies and the regulatory agencies) were the ones communicating. The original guidance was published back in 2009, and its most recent amendment was made in August 2020 – but cattle producers and the industry as a whole did not get a chance to comment, as it is only guidance.
“This guidance is intended to assist sponsors who wish to apply for approval of changes to approved new animal drugs that require the FDA to reevaluate safety and effectiveness data,” Johnson explained. “The goal is to create consistency in how such applications are handled by the sponsors and the Office of New Animal Drug Evaluation.”
(The guidance spells this out on its first page: “In general, FDA’s guidance documents do not establish legally enforceable responsibilities. Instead, guidances describe the agency’s current thinking on a topic and should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited. The use of the word should in agency guidances means that something is suggested or recommended, but not required.”)
The aim is simply to standardize dosage forms and the route of administration, to add target animals, to add indications and to note any changing of the concentration of active ingredients, specifically on product labels. GFI #191 is administrative guidance attempting to clarify and provide direction for sponsors – the pharmaceutical companies.
The new guidance lists two variants for “beef calves” – beef breeds only, no crosses, nursing from birth until weaning. These were formerly referred to as “suckling beef calves.” Variant 1 are those under two months of age, considered pre-ruminating and nursing their mothers. Variant 2 are those two months and older, considered ruminating and nursing until weaning.
“That 60-day cutoff is a big change, but if we can implant at 30 days, we can add another at 60 days,” Johnson clarified. “Suckling calves are basically the same as before but now with age divisions. Stocker calves, same as before.”
There are three variants in the new guidance for beef steers and heifers. These are weaned, castrated males or female cattle (beef and dairy breeds) intended for slaughter, housed in any setting and receiving their diet from any source.
- Variant 1: Growing beef steers/heifers on pasture (stocker, feeder and slaughter): These are weaned animals maintained on pasture and receiving the majority of their diet from grazing – “pretty straightforward and a typical grazing situation,” according to Johnson.
- Variant 2: Growing beef steers/heifers in a dry lot: These are weaned animals maintained in a dry lot receiving the majority of their diet from harvested forage (possibly with a supplement).
“This caught people by surprise. It’s not a confinement situation,” Johnson said. “There is not a single implant approved for a dry lot situation.” Johnson believes this describes a holding situation, not a growing one.
- Variant 3: Growing beef steers/heifers fed in confinement for slaughter: These are weaned animals intended only for slaughter and confined in group pens and fed a progressively high-energy diet ad libitum as their sole ration until slaughter. They may be referred to as feed yard or feedlot cattle (and includes animals in a grow yard – those in confinement fed moderate- to high-roughage diets as their sole ration). This variant defines what a grow yard is – and it’s the same as a finishing yard.
“There’s a new production phase with the dry lot; feedlot cattle are basically the same as before, but there’s now a separate subset for grow yards,” Johnson said. Notably, those using GETs can only use one implant per variant.
While there was no discussion of these changes with producers, the FDA sent a letter to the industry in mid-2021 informing them of the changes in the guidance. “The FDA assures beef cattle producers that approved, over-the-counter implants will remain available … These products have a variety of approved conditions of use and the FDA has recognized that the labeling for certain products may be unclear to the end user, particularly with regard to repeat implantations,” Johnson quoted from the letter. “To address this issue, the FDA has initiated a process to work with the drug sponsors to clarify the labeling of the affected beef cattle ear implant products.”
He said that what producers are concerned about is the reimplantation verbiage, since some users do that.
Per the FDA, as of June 30, new labels will be required on GETs. The agency gave producers an 18-month grace period to create new game plans regarding their use of the implants.
To get a reimplantation claim on a label now, the industry will need to prove the practice’s efficacy, its animal safety, undergo an environmental assessment and prove human food safety regarding residues. “We need to prove two implants are better than one,” Johnson clarified.
“The encouraging thing is the sponsors are working with the FDA to try to continue business as usual,” he added. “That’s good, because the technology is more vital now with the high cost of production.”
To read GFI #191 in its entirety, go to fda.gov/media/70423/download.
by Courtney Llewellyn
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