Estimating mouse and rat use in American laboratories by extrapolation from Animal Welfare Act-regulated species
Authors: Larry Carbone
Journal: Scientific Reports (2021)
Discipline: Multidisciplinary
Keywords: United States; welfare protections; vertebrate animals; research; Animal Welfare Act
Affiliations: University of California San Francisco, San Francisco, CA, 94117, USA. .

Abstract:  Alone among Western nations, the United States has a two-tier system for welfare protections for vertebrate animals in research. Because its Animal Welfare Act (AWA) excludes laboratory rats and mice (RM), government veterinarians do not inspect RM laboratories and RM numbers are only partially reported to government agencies1. Without transparent statistics, it is impossible to track efforts to reduce or replace these sentient animals' use or to project government resources needed if AWA coverage were expanded to include them. I obtained annual RM usage data from 16 large American institutions and compared RM numbers to institutions' legally-required reports of their AWA-covered mammals. RM comprised approximately 99.3% of mammals at these representative institutions. Extrapolating from 780,070 AWA-covered mammals in 2017-18, I estimate that 111.5 million rats and mice were used per year in this period. If the same proportion of RM undergo painful procedures as are publicly reported for AWA-covered animals, then some 44.5 million mice and rats underwent potentially painful experiments. These data inform the questions of whether the AWA needs an update to cover RM, or whether the NIH should increase transparency of funded animal research. These figures can benchmark progress in reducing animal numbers in general and more specifically, in painful experiments. This estimate is higher than any others available, reflecting the challenges of obtaining statistics without consistent and transparent institutional reports. 

Retracted: No

PubPeer comments:
 A commentary about this article was published today in Science s website https: www.sciencemag.org news 2021 01 how-many-mice-and-rats-are-used-us-labs-controversial-study-says-more-100-million  Others in the biomedical community disagree. The new analysis is u201cfundamentally flawed,u201d and the numbers are u201cinaccurate and vastly overstated,u201d says Nadia Rosenthal, scientific director of the Jackson Laboratory, which supplies a broad spectrum of mouse strains to universities and other institutions. Spending and shipping numbers from Charles River Laboratories, the worldu2019s largest commercial distributor of rodents, suggest commercial breeders supply, at most, 15 million mice and rats to U.S. labs every year, Rosenthal says. Combined with what labs themselves likely breed, she says the total number of those animals is likely closer to 20 million. Bennett faults the study for extrapolating from a handful of top-funded academic institutions to more than 900 other biomedical facilities, including less well-funded academic centers, pharmaceutical companies, and contract research organizations. u201cIf the same ratios of mice and rats donu2019t hold at these places,u201d she says, u201cthe entire exercise is invalid.u201d ,