Should you count your mice before they’re weaned?
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Jerald Silverman, DVM, Column Coordinator

Lab Animal 35(1), 2006

Should you count your mice before they’re weaned?

In common with the practice at many other institutions, the animal facility at Great Eastern University did not include neonatal mice in the census count until they were weaned. It was also common for investigators to euthanize transgenic mice that did not have the needed genotype for a particular research project. These two practices in combination provided an opportunity for some researchers to avoid paying per diem charges on their superfluous transgenic mice by euthanizing them before they were weaned. Of course, because the animals were never counted on the census, they also were never subtracted from the number of animals approved by the IACUC for that study. This chain of events never raised any eyebrows at Great Eastern until the Committee’s unaffiliated member nonchalantly asked about the need to  count the tadpoles that were part of another study.

“I was wondering,” said Pat Waite, “if we’re supposed to count tadpoles as ‘animals’ or if we’re supposed to wait until they pretty much change into frogs?”

“That’s a good question” replied Larry Cristofini, the IACUC Chairman. “Since tadpoles are, in the IACUC’s opinion, self-sustaining animals, we have always counted them as soon as they are capable of feeding themselves. In other words, similar to what we do for zebrafish fry.”

“Okay,” said Waite, “but that leads me to another question. If we count tadpoles as soon as they are capable of feeding themselves, how come we don’t count mouse pups, including transgenic pups, as soon as they are born? They’re perfectly capable of nursing their dams at that time. Not only that, but I’ve been told many times that pups start eating solid food by themselves before they are weaned. Don’t we have two standards? Shouldn’t we really put mouse pups on the census as soon as they’re born?”

“Don’t worry about it, Pat” said Cristofini. “We’ve always done it this way and we’ve never had any complaints from OLAW [Office of Laboratory Animal Welfare], nor have I ever seen anything that OLAW has written to contradict what we do. Not only that, but when we have our AAALAC [Association for Assessment and Accreditation of Laboratory Animal Care International] site visits, nobody has ever questioned us. I think we can take that to mean that we’re in compliance with federal regulations.”

Is Great Eastern in compliance with their method of accounting for neonatal mice, or are OLAW and AAALAC just not making an issue of a common practice?

RESPONSE
Pool the pups

H. Hugh Harroff, Jr., DVM, DACLAM & David G. Watson, PhD

The unaffiliated member of the Great Eastern IACUC has a valid point in thinking that the mouse pups in this situation should be counted in the animal census from the time of birth. We believe that the IACUC has three issues to address in this situation.
First, should the investigator pay per diem charges for all of the mouse pups born to the dams on the study, even though they may not be genetically suitable for inclusion in the study? This is a minor issue for which there can be local answers without regard to regulatory considerations. We believe the cost of housing the extra pups is negligible and should be covered by the ‘overhead’ or operating funds of the institution.

Second, should the census include all of the mouse pups born to the dams on the study? As stated earlier, we concur with Waite (the unaffiliated member) that there is an inconsistency in the institution’s counting of animals (tadpoles versus mouse pups) and adding them to the census. We suggest that a satisfactory solution would be for the Great Eastern IACUC to generate and approve a generic protocol for animals being held in a ‘pool’ pending assignment to a research study. The investigator on this protocol would be a member of the University’s Laboratory Animal Resources. The protocol would cover all species that might be held pending future assignment to a study, including the mouse pups; it would also specify procedures for animal care and treatment and would describe in detail the planned tests (e.g., genetic monitoring, complete blood count, serum chemistry) in determining suitability of the animals for assignment to research studies. Finally, the protocol would specify the disposition of unsuitable animals such as euthanasia and the method of euthanasia. At the time of birth all of the mouse pups would enter this ‘pool’ protocol, which would automatically include them in the animal census. Because genetic monitoring would be a decisive issue in determining the suitability of the mouse pups, the protocol would probably fall into USDA pain category C or D.

Third, should all of the mouse pups born to the dams assigned to the study be counted against the total allotted by the IACUC for the protocol, even though genetic monitoring may eventually determine that many are unsuitable for the study? It is absolutely not permissible to exceed the number of animals allotted to a protocol by the IACUC. We believe that the ‘pool’ protocol described earlier would also solve this problem. With the ‘pool’ protocol, there would be a description of the criteria used to determine a pup’s suitability for inclusion in the study, a description of the methodology used to determine suitability (e.g., methods of genetic monitoring), and a description of the euthanasia method for the unsuitable mouse pups. Therefore, only animals that satisfy the study’s mandatory genetic and other criteria would actually become part of the total number of study animals.

As the Great Eastern IACUC Chairman observed, we are not aware of any pronouncements on this issue from OLAW or AAALAC. We feel confident, however, that the creation and approval of a ‘pool’ protocol with open-ended animal numbers would comply with the intent of the applicable laws and regulations, in that all animals would be covered by an IACUC-approved protocol and would be included in the institution’s census and reports generated for regulatory agencies.
Harroff is Laboratory Animal Medical Officer and Watson is IACUC Chairman, 59th Clinical Research Squadron, 59th Medical Wing, Wilford Hall Medical Center, Lackland AFB, TX.

RESPONSE
Silence not equal to compliance

Sarah L Froebel BS, BA, RLATg
In this scenario the IACUC Chair states that Great Eastern has not “had any complaints from OLAW…”, nor has he seen “… anything that OLAW has written to contradict…” the animal tracking practices at this institution. He goes on to say that “when we have our AAALAC site visits, nobody has ever questioned us,” and so the Chair interprets this silence as an acknowledgment of compliance. However, there may be a reason these outside agencies remain quiet about the University’s animal tracking practices; OLAW and AAALAC may not even be aware of the actual procedures.

The IACUC Chair’s mention of OLAW suggests that the University has a Public Health Service (PHS) Assurance statement, which would cover all vertebrate animals. This Assurance statement is usually the primary document that defines the relationship between research organizations and the PHS Policy on Humane Care and Use of Laboratory Animals (PHS Policy). The majority of correspondence between a research institution and OLAW is on paper. Because PHS-assured establishments have the responsibility to self-report any deviations from this document, OLAW knows mostly only what is reported to them.

In addition, PHS Policy requires adherence to the Guide for the Care and Use of Laboratory Animals (Guide), which serves as the main resource used by AAALAC to assess animal care programs. Great Eastern showed compliance with the Guide at the time of AAALAC accreditation, but it seems that they may have become negligent since then. Once again, the accredited institution’s interaction with AAALAC consists at a minimum of annual reports and triennial visits.

Even though the PHS Policy and the Animal Welfare Act do not explicitly state how institutions are to track the use of animals according to approved protocols, there is an indirect requirement for them to monitor and document the number of animals being used. When to count neonatal mice would be determined by whether they, or their dam, are actually being used. If they are involved in painful procedures or are at a stage where they can perceive pain, their use and numbers need to be clearly justified on the protocol submitted to the IACUC. Once the protocol has IACUC approval, then it becomes the IACUC’s responsibility to monitor compliance through appropriate means.

There may not be questions raised if it were just a breeding colony and the pups (or fetuses) did not undergo any type of manipulation; as long as they are maintained with the identified dam as a litter, investigators could account for survivors at weaning. The practice of investigators genotyping pups before weaning by means of a tail clip (a stressful/painful procedure), choosing to euthanize them because of an inappropriate genotype, and then not counting these animals as used, would raise concerns with both AAALAC and OLAW. In addition, these agencies would have reason to question the university’s animal tracking practices if visitors from these agencies saw, heard, or read something contrary to the practices stated by the university. However, because most correspondence with these two organizations is by paper or infrequent visits, there are no questions about Great Eastern’s animal tracking procedure.
Froebel is Director of Animal Programs and Laboratory Support, Middlebury College, Middlebury, VT.

RESPONSE
Start counting

Barbara A. Cox, PhD, Malcolm Low, MD, PhD, Kim Saunders, DVM, DACLAM & Charlotte Shupert, PhD, CIP

No, Great Eastern is not in compliance with their accounting for neonatal mice.

The ARENA/OLAW Institutional Animal Care and Use Committee Guidebook includes the following guidance: “Tracking animal use becomes more complicated when investigators maintain breeding colonies. Keeping track of animal usage may be accomplished by requiring that investigators with breeding colonies maintain accurate records. Investigators can be required to report to the designated office, at regular intervals, the number of animals born, weaned, or used in studies. This report can be tallied against the numbers in the approved protocol1.”

This passage makes it very clear that the census of the number of animals used in the IACUC-approved protocol must include the neonatal mice. Moreover, the record keeping and reporting are the responsibility of the investigator. The IACUC examines the numbers given in the report against those approved in the protocol as part of postapproval monitoring. The passage does not specify the time frame for reporting, just regular intervals. It would be simple to have the report as a part of the annual review; this would allow an adjustment of the average daily census of mice to include the number of mice born (required for PHS Institutional Assurance).

With these steps taken, Great Eastern would be compliant.
Although OLAW and AAALAC may not currently make an issue of this common practice, it is probable that this seeming indifference will change in the future. When the Guide was published in 1996 there were fewer transgenic breeding colonies than there are today. During the previous decade the use of transgenic mice has markedly increased. The Institutional Animal Care and Use Committee Guidebook, published in 2002, is unequivocal about the need to count neonatal mice. Therefore, AAALAC, in future site visits, will undoubtedly look for a record of the number of neonatal mice in the IACUC protocols and also in IACUC postapproval monitoring records.

1.    ARENA/OLAW. Institutional Animal Care and Use Committee Guidebook 2nd Edn. C.4 (Office of Laboratory Animal Welfare, Bethesda, MD, 2002).

Cox is IACUC Manager, Low is Marquam Hill IACUC Chair, Saunders is Director, Department of Comparative Medicine, and Shupert is Associate Director of Research Integrity, Oregon Health and Science University, Portland, OR.

A Word from OLAW

In response to the questions posed in this scenario, the Office of Laboratory Animal Welfare (OLAW) offers the following clarification and guidance:

The PHS Policy is applicable to live vertebrate animals used in research, research training, and biological testing, and clearly applies to pre-weanling animals.

OLAW only requires reporting of average daily inventories of animals, by species, in new and renewal Animal Welfare Assurances. OLAW uses this information as part of its assessment of the overall adequacy of the institutional program (e.g., personnel, facilities) to support the institution’s research activities. Although mouse dams and their unweaned litters may be considered as units for inventory purposes, litter sizes need to be determined with sufficient frequency to ensure that space recommendations of the Guide for the Care and Use of Laboratory Animals are appropriately applied.

The PHS Policy does not explicitly require an institutional mechanism to track animal usage by investigators in IACUC-approved activities; but it does require that proposals specify and include a rationale for the numbers of animal to be used, and that the number be limited to the minimum necessary to obtain valid results. Accordingly, institutions need to appropriately monitor and document numbers of animals acquired (through breeding or other means) and used in approved activities. Monitoring should not exclude the disposition of animals inadvertently or necessarily produced in excess of the number needed or which do not meet criteria (e.g., genetic) established for the specific study proposal.

Note that mice (Mus) are not a USDA-covered species and the PHS Policy does not require the application of USDA pain categories.

Carol Wigglesworth
Acting Director
Office of Laboratory Animal Welfare, OER, OD, NIH, HHS

©2006 Lab Animal

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