Guidelines for Acclimation for Newly Received Laboratory Animals

“Transportation unavoidably causes stress in animals.  Although stress is not always an adverse experience and is a necessary and regular aspect of life, it causes changes in an animal’s physiological status during transportation and for some period thereafter. Utilizing transported animals before their physiological status normalizes can have considerable and unintended effects on research results.”  “Stress associated with transportation has widespread effects on physiological systems in laboratory animals including changes in the cardiovascular, endocrine, immune, central nervous and reproductive systems.“ (1)

The Guide for the Care and Use of Laboratory Animals and the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching recommend a period of stabilization and acclimation for newly arrived animals.  This document provides standard recommendations to PIs regarding appropriate acclimation times for animals following transport prior to their use in experiments.

Acclimation:  This term refers to the process/period during which newly arrived research animals are allowed to fully recover from shipping and adjust to new surroundings, feed, light/dark cycles, cage/pen mates, and personnel prior to being used on research, teaching, or testing protocols.  It also provides a period for physiologic, psychological, and nutritional stabilization prior to use. (2)

Quarantine:  Quarantine is the separation of newly received animals from those already in the facility until the health and possibly the microbial status of the newly received animals have been determined with the goal of minimizing the chance for introduction of pathogens into an established colony.  Quarantine periods for animals may vary in duration based on the species, the source and health status of the incoming animals, and regulatory requirements.  This policy does not address quarantine and researchers are encouraged to contact DLAR Veterinarians for further information on quarantine requirements for specific situations.

Researchers are strongly encouraged to ascertain how physiologic changes associated with transport may affect the specific research to be conducted as well as the length of time necessary for confounding physiologic changes to normalize.  Longer periods for acclimation, conditioning, and/or training of animals may be required for specific protocols based on individual research needs.

For example, it has been reported that subsequent to transportation:

• Immunologic functions are inhibited and/or altered (5, 6, 7, 8, 9)
• Cortisol/Corticosterone levels are elevated (5, 6, 7, 8, 10, 11)
• Serum chemistry parameters are affected (3)
• Myocardial antioxidant enzyme activity is increased (12)
• Feed and water intake and body weight is decreased (10, 13, 14)
• Heart rate, body temperature, and activity is altered (14)

Guidelines listed below are for minimum recommended periods of stabilization and acclimation and vary with species.  They are applicable to animals acquired from approved vendors and of known health status.  Information on approved vendors for each species can be obtained from DLAR.  Longer periods of acclimation may be warranted based on mode and length of transport, source, or other considerations relevant to the health of the animal as determined by the veterinarian.  NHP (non-human primate) species require longer acclimation, quarantine and special procedures.  These recommendations do not apply to non-human primates and the DLAR veterinary staff should be contacted for information on the current requirements for these species.

Rodents: 

Rodent species should have a minimum acclimation period of 3 days (72 hours) prior to use in survival surgery or long-term experiments. 

Euthanasia and tissue harvest may be performed on the day of arrival. 

Nonsurvival surgery or other terminal nonsurvival procedures can also be performed the day of arrival. However, the PI is advised to consider the effect that shipping stress may have on the experimental data.

Non-Rodents:

Non-rodent species to include dogs, cats, rabbits, birds, and livestock species should have a minimum acclimation period of 1 week (7 days) prior to major survival surgery or chronic protocols involving particularly sensitive parameters. 

A minimum period of 3 days (72 hours) is recommended prior to non-survival procedures or minor procedures (e.g., minor surgery).  However, the PI is advised to consider the effect that shipping stress may have on the experimental data. 

Euthanasia and tissue harvest may be performed on the day after arrival.

1. Obernier JA, Baldwin RL. Establishing an appropriate period of acclimatization following transportation of laboratory animals. ILAR J. 2006;47(4):364-9

2.  NRC [National Research Council] 1996.  Guide for the Care and Use of Laboratory Animals.

3. FASS [Federation of Animal Science Societies] 1999.  Guide for the Care and Use of Agricultural Animals in Agricultural Research and Testing.

4. NRC [National Research Council] 2006. Guidelines for the Humane Transportation of Research Animals

5. Aguila HN, Pakes SP, Lai WC, Lu YS. The effect of transportation stress on splenic natural killer cell activity in C57Bl/6J mice.  Lab Anim Sci. 1988 38: 148-151

6. Landi MS, Kreider JW, Lang CM, Bullock LP. 1982. Effects of shipping on the immune function in mice.  Am J Vet Res 43: 1654-1657

7. McGlone, JJ et al. Shipping stress and social status effects on pig performance, plasma cortisol, natural killer cell activity, and leukocyte numbers. J Anim Sci 1993 Apr 71(4):888-96.

8. Hicks TA et al. Behavioral, endocrine, immune, and performance measures for pigs exposed to acute stress. J Anim Sci 1998 Feb 76(2):474-83.

9. Murata H, et al. Influence of truck transportation of calves on their cellular immune function. Nippon Juigaku Zasshi 47: 823-827.

10. Tuli Js et al. Stress measurements in mice after transportation. Lab Anim 1995 29:132-138.

11. Bean-Knudsen DE and Wagner, JE. Effect of shipping stress on clinicopathologic function in F344/N rats. Am J Vet Res 1987 Feb. 48(2): 306-8.

12. Rowland RT, et al. Transportation or noise is associated with tolerance to myocardial ischemia and reperfusion injury. J Surg Res 89: 7-12.

13. Knowles TG, et al. Effects on cattle of transportation by road for up to 31 hours. Vet Rec 145: 575-582.

14. Capdevila, S et al Acclimatization of rats after ground transportation to a new animal facility. Lab Anim 2007, Apr 41(2):255-61.