Frequently Asked Questions

Which kind of bedding is used at Taconic?

Bedding is comprised solely of hardwood chips and is supplied in 30 lb. bags. The bags are made of 2-ply Kraft paper and are fully autoclavable. All chip is free of splinters, excessive dust, and foreign particles. View pricing information.

How many animals do Taconic ship per cage?

All Taconic commercial mice and rats are placed in their shipping cartons (the Taconic Transit Cage™ (TTC™)) with their Barrier Units of origin. The number of animals placed in each TTC™ varies depending upon the size of the animals. Learn more by going to Taconic Transit Cage™ Density.

I have read that a particular mouse model was obtained from Taconic, but I cannot find this model in your catalog. Does Taconic carry mice that are not in the catalog?

When the Taconic catalog goes to press, we list all of our commercially available animal models. Our website is the most current source for this information, including models which may become available after catalog press time. Be sure to check our Commercial Models List and our Emerging Models.

In addition to our commercial and emerging models, Taconic raises many animal lines under contract to various government, university, and commercial customers. In publication, Taconic may be referenced as the source of these animals in a context of geography, animal health, and environment.

Our breeding contracts are confidential arrangements with each sponsor, we are not at liberty to divulge the identity of those lines. We will arrange shipment of these mice to any destination, so long as it is at the direction of the sponsor.

When you read a recent publication that cites Taconic as the source of the model, it is best to consult our current catalog or website, including the emerging models section. If the model is not listed there, it is likely a contract line and you must contact the owner of that line and negotiate permission to obtain them. (The recent author may not be the owner, but a good place to start.) You must make collaboration agreements with the owner directly. They will then contact us with approval to provide the quantity of these mice to you, and we will contact you to coordinate the specifics (delivery address, date, any veterinary questions, etc.)

What is the best host for xenograft studies?

The most appropriate answer to this question is that it depends on the cell line(s) to be used - any cell line may have performance that varies from one host to another.

There are, however, some factors to consider.

nude vs. scid
All nude mice are T cell deficient. That is the minimum requirement to host a human tumor graft. Most of the tumor lines we have worked with grow quite well in the basic nude mouse. scid mice are also T cell deficient, and are B cell deficient too.

Inbred vs Outbred
Taconic provides these immune deficiencies on outbred backgrounds (NCR nude, ICR scid) and also on inbred backgrounds (B6 and BALB/c nude, C.B-17 scid). The use of an inbred model offers more consistent (homozygous) background genetics. The outbred versions tend to be larger, and since they produce larger litters, we can offer them at lower prices.

Role of NK cells
Certain cell lines may be susceptible to NK cell activity. In this case, a mouse that is also NK cell deficient may be necessary. Taconic models which lack T, B, and NK cells include the scid-beige and the CIEA NOG mouse®. The CIEA NOG mouse® is the most immunodeficient mouse available. It has superior engraftment capability and is a good model to try if you experience low take rates or inconsistent growth in nude or scid models.

Cell line history
Taconic has worked with many cell lines that have performed very well in the NCR outbred nude mouse.

Recommended course of action.

  1. Consult the literature to determine which host animals have been used for the cell line, or cell type, you wish to use. Beware of papers that use the nondescript term "athymic nude mice."
  2. Determine if your study requires an inbred host. For studies that use the mouse as a tumor host, and study a drug:tumor interaction, an outbred mouse is often sufficient. Studies which target the mouse response to a xenograft may utilize an inbred host to present consistency from one animal to the next within study groups.
  3. Perform a pilot study with the simplest solution. The NCR nude mouse and ICR scid mice are both cost effective solutions and should be ruled out before more expensive mice are considered.

What is the difference between "Wild Type" and "Control" mice for TTMs™ (Taconic Transgenic Models™)?

Control mice for TTMs™ do not carry any genetic manipulation, and have a genetic makeup that is approximate to the TTM™ in question. For a TTM™ that is fully backcrossed, the backcross strain is often the control strain of choice. For example, Model APOE has been backcrossed to a C57BL/6 background, so C57BL/6 mice are the appropriate control strain.

Wild type mice also do not carry any genetic manipulation, but they are produced in the same litters as the TTM™ mice. They may also be referred to as "littermate controls". In this respect they share common genetics with the TTM™ (aside from the manipulated gene of interest) and have similar environmental upbringing as well. For example, APPSWE mice (Model #1349) are on a mixed background and wild type mice are available for use as controls.

The Taconic catalog and website list wild type mice when available, or the recommended background control strain.

Is health testing included in animal production contracts?

Yes. Whenever Taconic provides custom breeding in our MPF™ (Murine Pathogen Free™) production colonies, the IHMS™ animal health surveillance program is continued and covered by the weekly cage rates.

Can I obtain a health report with my shipment?

Yes. Upon special request, a signed health report can be printed for each source barrier and attached to the shipment. Each report is signed by the attending veterinarian. Since Taconic health reports are available online, most customers prefer to print them directly from this website, prior to the arrival of the shipment.

How does Taconic Surgery design their cannulations for vascular access?

All of Taconic's vascular cannulations terminate with an access port that exits the skin between the shoulder blades. These ports are made of plugged tubing and will accept 22 or 23 Gauge needles for flushing, filling and sampling. With this location, the rats and mice cannot reach the port to damage it, but they must be housed and shipped individually.

Each cannulation procedure has a Care and Use document that is available in the Surgery section on This document should be reviewed by staff prior to placing their order. Our surgical staff would be glad to discuss this in detail to assure successful use of our modified animals.

What are DIO mice?

The term DIO refers to Diet Induced Obesity. Rats and mice are prone to obesity when fed an experimental diet with elevated fat content. The DIO diet derives 60% of the caloric content from fat, compared to a standard diet that derives 10% of energy content from fat. Taconic maintains an inventory of C57BL/6NTac male mice maintained on a DIO diet beginning at 6 weeks of age and continuing up to 26 weeks of age (available inventory may vary). Mice from this inventory display the obese phenotype (heavier weight, increased body fat content, etc.) and may be immediately enrolled in studies without a time-consuming preparation phase.

What is an Emerging Model?

An Emerging Model is an animal line sponsored for distribution by Taconic on behalf of the originator of the line or other sponsoring institution. Emerging Models are raised by Taconic with all of our standard QC (health profile, genotyping, etc.) and available through our worldwide distribution network. Sponsorship permits broad distribution of interesting models to researchers worldwide. Because the sponsor sets colony size and access conditions, some models may be available only in limited quantities. Material Transfer Agreements (MTAs) may be required before ordering certain models. View our complete list of Emerging Models. If you are interesting in learning more about distribution of models via Taconic's Emerging Models program, please contact your Area Technical Representative.

How does Taconic report gestational age of timed pregnant animals?

The Taconic convention for timed pregnancy identifies the first day of pregnancy as the morning on which a vaginal plug (mice) or sperm positive smear (rats) was observed. This is called day 1 of gestation. Charles River uses this same convention. However, Harlan calls this first day of observation to be day 0.

All orders timed pregnant animals are documented with the gestational age on their scheduled delivery date as well as the date the pregnancy was first detected (plug date / sperm positive date) for any additional calculations.

Do nude rats have any hair?

Yes, they do. Nude rats may have very sparse hair on their bodies and around their face. The hair growth cycle in these animals does persist with hair regrowing on an average frequency of every six weeks or so. This will be a transient regrowth and will not persist very long. This does not affect their genetic immune deficiency, but may have subtle impact. For example, nude rats may require shaving prior to surgery. Even in their hairiest presentation, nude rats will be easily identified!

This same observation is true of nude mice.

What is young mortality syndrome in APP mice?

APPSWE mice, a transgenic model of Alzheimer's disease, exhibit a mortality window at 7 to 9 weeks of age, at which time 5-20% of the male mice may expire. This mortality is unpredictable by cage side observation; some mice just appear dead upon the next observation. When we observe these mice rigorously at several time points per day, we are unable to detect any indicators of impending mortality. Occasionally, a dead mouse is found in a position that suggests a neurologic seizure occurred, but this hypothesis has not been substantiated by anything beyond the observation. Because of the rapid degradation of brain tissue post-mortem, we have not been able to collect any samples for neurohistology examination.

This condition does not affect other Taconic strains, and does not affect the wild type mice. It is likely that this mortality is linked to the APPSWE gene, though the mechanism has not been determined.

Taconic recommends that these mice be purchased at 10 weeks of age or greater. Mice at these ages are safely beyond the mortality window.