Abstract
The United States Food and Drug Administration (FDA) approved two β-adrenergic agonists (βAA) for in-feed administration to cattle fed in confinement for human consumption. Anecdotal reports have generated concern that administration of βAA might be associated with an increased incidence of cattle deaths. Our objectives, therefore, were to a) quantify the association between βAA administration and mortality in feedlot cattle, and b) explore those variables that may confound or modify this association. Three datasets were acquired for analysis: one included information from randomized and controlled clinical trials of the βAA ractopamine hydrochloride, while the other two were observational data on zilpaterol hydrochloride administration to large numbers of cattle housed, fed, and cared for using routine commercial production practices in the U.S. Various population and time at-risk models were developed to explore potential βAA relationships with mortality, as well as the extent of confounding and effect modification. Measures of effect were relatively consistent across datasets and models in that the cumulative risk and incidence rate of death was 75 to 90% greater in animals administered the βAA compared to contemporaneous controls. During the exposure period, 40 to 50% of deaths among groups administered the βAA were attributed to administration of the drug. None of the available covariates meaningfully confounded the relationship between βAA and increased mortality. Only month of slaughter, presumably a proxy for climate, consistently modified the effect in that the biological association was generally greatest during the warmer months of the year. While death is a rare event in feedlot cattle, the data reported herein provide compelling evidence that mortality is nevertheless increased in response to administration of FDA-approved βAA and represents a heretofore unquantified adverse drug event.
Highlights
The United States Food and Drug Administration (FDA) approved two b-adrenergic agonists for in-feed administration to cattle that are fed in confinement for human consumption [1,2]
Ractopamine hydrochloride (RH) was the first b-adrenergic agonists (bAA) approved in cattle; further, RH may be used in a variety of dosages and has been approved for administration to swine and turkeys
Zilpaterol hydrochloride (ZH), the second bAA approved by the FDA, may only be used at a single rate of inclusion in cattle feeds
Summary
The United States Food and Drug Administration (FDA) approved two b-adrenergic agonists (bAA) for in-feed administration to cattle that are fed in confinement (i.e., typically feedlot operations) for human consumption [1,2]. Zilpaterol hydrochloride (ZH), the second bAA approved by the FDA, may only be used at a single rate of inclusion in cattle feeds It is included in cattle feed for 20 to 40 days prior to slaughter; in contrast to RH, a 3-day period during which ZH may not be administered must be observed prior to shipment to the abattoir (i.e., slaughter withholding). In addition to their production uses in food-animal production, b-adrenergic agonists are routinely used in human clinical medicine for various conditions such as acute therapeutic intervention and maintenance care of asthma and chronic obstructive pulmonary disease (i.e., COPD). Our objectives were to: a) quantify the association between bAA administration and mortality in feedlot cattle, and b) explore those variables that may confound or modify this association
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
