UT Southwestern IACUC Policy IACUC # 105
Approval Date:___2/10/06______ 1 of 1
Rat Overcrowding and Acceptable Cage Density
Rationale:
The Public Health Service requires that institutions base their animal care and use programs on the ILAR
Guide for the Care and Use of Laboratory Animals. The UT Southwestern Institutional Animal Care and Use Committee (IACUC) must comply with the national standards and recommendations contained within the Guide when establishing rat cage populations.
Policy:
The IACUC requires that PI’s comply with the cage space requirements for rats according to the Guide.
Applicability:
This policy applies to all rats housed for research purposes.
Exceptions:
Exceptions to the Rat Overcrowding and Acceptable Cage Density policy are considered to be an exception to the Guide and require a written request and subsequent approval by the IACUC. The exception request must provide adequate scientific justification for not following the Guide.
Instructions:
Required space for rats as taken from the
Guide for the Care and Use of Laboratory Animals.
Large Shoe-Box Cages (9x17 inch, 153 sq inch)
<table align="center" border="1" width="60%"><tbody> <tr> <td>
Body Weight: </td> <td> Maximum Number Rats per Cage:</td> </tr> <tr> <td> <100g</td> <td> 7</td> </tr> <tr> <td> 100-200 grams post weaning</td> <td> 5</td> </tr> <tr> <td> 200-300 grams</td> <td> 4</td> </tr> <tr> <td> 300-400 grams</td> <td> 3</td> </tr> <tr> <td> >400grams</td> <td> 2</td> </tr> </tbody></table> Large Ventilated Cages in NG (17.5 x 12 inch, 210 sq inch)
<table align="center" border="1" width="60%"><tbody> <tr> <td>
Body Weight: </td> <td> Maximum Number Rats per Cage:</td> </tr> <tr> <td> 100-200 grams post weaning</td> <td> 9</td> </tr> <tr> <td> 200-300 grams</td> <td> 7</td> </tr> <tr> <td> 300-400 grams</td> <td> 5</td> </tr> <tr> <td> >400grams</td> <td> 3</td> </tr> </tbody></table>
Breeding:
• Rats are bred in male: female ratios of 1:1 or 1:2. The male, female and litter may remain together until the pups are weaned. The litter must be weaned prior to the delivery of a second litter by the same female. If rats are bred in a male: female ratio of 1:2, then one pregnant female must be removed to another cage before parturition.
• Date of birth for the litter must be recorded on the cage card by the investigator.
• A cage is overcrowded if a new litter is born before the older litter is weaned.
• A cage is overcrowded if two litters from separate females coexist in the cage or a litter remains with the female beyond 21 days of age.
• Weaning beyond 21 days of age is a special circumstance and requires either written Veterinarian approval (if done sporadically for health reasons) or prior IACUC approval (if done routinely by the laboratory).
If an overcrowded cage is found, ARC personnel will notify the Principal Investigator or Manager of the colony. If the overcrowded cage is not corrected within 48 hours of being tagged, older pups or excess adults, will be removed and placed in another cage. The original cage will be labeled with the date, number of animals moved, and an identifying number or letter. New cages will be labeled with the name of Principal Investigator, protocol number, the date, the identifying number, and the number of rats.
The Principal Investigator will be charged the standard technician time rate for separating rats that have gone beyond the approved weaning age or are housed in overcrowded conditions.
Colonies will be designated as having an overcrowding problem and put on an IACUC monitoring list if the percent of overcrowded cages is above 0.4% of the total monthly cage census.
Repeated violations of the cage density policy will result in the following corrective action.
• The first month a PI's rodent colony is determined to have an overcrowding problem (defined above), a written warning will be issued in addition to the standard ARC technician charge for separating animals.
• The second consecutive month a PI's colony is found to have an overcrowding problem, a $25.00 charge per overcrowded cage will be issued in addition to the standard ARC tech charge for separating any animals. A letter will be sent to the Dean of the Medical School informing him of the problem. • The third consecutive month a PI's colony is found to have an overcrowding problem, a $50.00 charge per overcrowded cage will be assessed in addition to the standard ARC charge for separating any animals. In addition, the IACUC will require a written plan from the PI detailing how the overcrowding problem will be eliminated. If a plan is not provided or is not acceptable to the IACUC, the IACUC will consider restriction of the PI's privileges to conduct animal research and will determine whether the repeated overcrowding problem constitutes continuing noncompliance reportable to OLAW.
Contact Information:
For any additional questions concerning this policy, please contact the IACUC Manager at 5-6420.
