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IACUC Policy

Experiment Guidelines/Animal Care

IACUC Animal Care Veterinary Care Experiment Guidelines Surgery Anesthesia Euthanasia Safety Training
Housing and Husbandry Guidelines for Laboratory Animals
General

Checking Rooms

Room Conditions

Cage Conditions

Food

Water

Health 
Monitoring

Cage Space Requirements
 

 


 

Copyright 2003, University of Minnesota Board of Regents.

The University of Minnesota is an equal opportunity educator and employer.

The caging or housing system is an important factor in the physical environment of laboratory animals. It can influence the well-being of the animals and/or act as an experimental variable. Federal guidelines for use of vertebrate animals in research contain specific provisions for basic husbandry. Proper diet and a stress-free, sanitary environment are some of the greatest tools in preventing the development or transmission of disease. The following guidelines are used by RAR in developing our husbandry procedures. They are adapted from requirements in the Animal Welfare Act, the Guide for the Care and Use of Laboratory Animals, and from the collective experience of RAR animal care providers. If University investigators have received permission from the IACUC to provide their own animal care these guidelines apply. 

Checking Rooms

  1. All animal housing areas must be checked daily, including weekends and holidays, no exceptions.
  2. This check should include:
    1. Monitoring room conditions
    2. Monitoring animals for health problems
    3. Monitoring food and water levels
    4. Monitoring for proper cage/enclosure conditions
    5. Details of the needs for each of these items is provided below.
  3. Problems should be evaluated based on the potential for adverse effects on the animals and remedied as soon as possible.
  4. Documentation of daily checks should be provided in the form of a room Standard Operating Procedure (SOP), a log or a check list.

Health Monitoring

  1. Frequency
    1. Animal health status must be monitored at least once daily, including weekends and holidays, no exceptions.
    2. Animals with specific health problems, animals recovering from anesthesia, or animals on studies that have the potential for rapidly changing the animals’ condition (e.g. infectious disease, tumor induction, toxicity) may require more frequent monitoring.
  2. Clinical Signs of Disease
    1. Clinical signs of disease can be extremely variable depending on the species of animal and the condition being monitored.
    2. Changes in behavior, food or water consumption, fecal or urine output, reduction in grooming behavior, aggression, muscular rigidity, hair coat, reaction to handling can be nonspecific signs of distress or disease.
    3. More specific signs or objective measurements of organ dysfunction should be monitored if indicated by the animal’s condition or the expected impact of the experiment.
    4. Further information is available from RAR.
  3. Veterinary Care
    1. All animals used for research, testing or teaching at the University of Minnesota must have an attending veterinarian available. If animals are not housed in RAR associated facilities, the veterinary oversight should be indicated on the protocol.
    2. Veterinary care must be available on holidays and weekends as well as during work hours.
    3. Research Animal Resources can provide veterinary consultation on request.

Room Conditions

  1. General
    1. An animal room must be kept clean, quiet, and uncluttered. The use of procedure rooms is encouraged whenever possible. Research procedures which are permitted within the room include injections, blood collection, examinations and other noninvasive techniques. Procedures which are not permitted in the animal room, except in a vented biosafety cabinet, include surgery, euthanasia and necropsy. Exceptions may be made in special circumstances such as quarantine..
  2. Light
    1. Light levels should be adequate for the animal to perform normal behaviors and for the animal care giver to perform their duties. Diffuse lighting in the range of 130-325 lux are normal for mammal husbandry.
    2. The light cycle should be appropriate for the biology of the animal, if consistent with experimental goals. A diurnal 12 hour light cycle for most species and 14 hour light /10 hour dark for breeding colonies of rats and mice are standard. Reversal of the cycle or alteration of the cycle may be desirable depending on the experiment.
  3. Ventilation
    1. Ventilation for rooms housing mammalian species must be adequate to provide oxygen and remove chemical, biological, and heat waste. The standard rate is 10-15 air changes per hour. Lower levels may be acceptable if animal density in the room is low. Fresh air supply and 100% exhaust air to the outside is the standard ventilation requirement.
    2. Room ventilation should normally be adjusted to maintain room pressure relative to the corridor as positive for SPF animals or negative if the room is serving as an isolation room.
    3. Ventilation ducts and filters should be cleaned at least monthly.
  4. Temperature
    1. Temperature in rooms should be maintained in a range suitable for the species of animal and the animals should be protected from abrupt changes.
    2. A range of 68 F to 74 F is standard for mammals.
    3. Amphibians, reptiled, fish, birds and animals adapted to outdoor environments may have different needs.
    4. Temperature ranges for many animals are specified in the Animal Welfare Act and the Guide for the Care and Use of Laboratory Animals.
  5. Noise
    1. Animals may detect different sound frequencies than do human beings. Therefore, noise in animal rooms should be minimized whenever possible.
    2. Playing music in animal rooms is not allowed, although it may be permitted under some circumstances to provide enrichment or "white noise".
    3. Noise from mechanical equipment in adjacent areas should be avoided.
    4. Some species may experience reproductive problems when exposed to excessive noise.
  6. Sanitation
    1. Room surfaces should be constructed of material that is easily sanitized.
    2. Floors, counters and sinks should be cleaned daily.
    3. Other room surfaces, including cage racks, should be sanitized monthly.

Cage Conditions

  1. Identification
    1. All animals must be identified according to their protocol number, the name and phone number of the investigator, species, and should also include strain, sex, age and source.
    2. Rodents and smaller animals may be identified at the cage or rack level. Large animals must have individual identification.
    3. Identification is normally provided by a cage card, with additional marking of individual animals when needed. Groups of animals may be identified using one posting if all information is identical.
  2. Cage Space Requirements
    1. A major consideration is the provision of enough space to allow an animal to make normal postural adjustments and have normal intraspecific interactions (including avoidance).
    2. Cage space requirements are specified by federal guidelines and law. Exceptions must be approved by the IACUC.
    3. For mice, a standard "shoebox" type cage can hold 4 adult female mice or 5 adult male mice and the larger rat shoebox cage can house 2 adult rats (3 if each is less than 500 g). For other species enclosures should be measured and the animals weighed to determine if requirements are being met.
    4. The ultimate measure of whether or not cage space is adequate is the condition of the animal. If animal waste is excessive, or if significant aggression is occurring, the cage is too crowded.
  3. Type of Caging
    1. Grate type floors are generally used for large animals and rabbits for sanitary reasons. Solid floors may be necessary if the grate causes foot or leg problems.
    2. Solid bottom caging with bedding is the preferred type of caging for all rodents. Rodents over 600 g must have solid bottom caging, unless a wire bottom is necessary for scientific reasons. [Link to rationale]
    3. Breeding mammals must have a solid floor at least in a nest box, bedding and additional nesting material.
    4. Immunodeficient animals, or animals to be maintained specific-pathogen free may require housing that has been sterilized, usually by autoclaving.
    5. SPF rodents are usually housed in filter top caging to prevent transmission of diseases into or out of the cage. These cages must be handled in protective hoods using sterilants for anything that will touch the interior of the cage.
  4. Bedding Material
    1. Bedding material should be clean, dry, dust-free, absorbent, non-toxic and preferably soft.
    2. Typical bedding used for rodents include hardwood chip or ground corncob. Do not use aromatic softwood (e.g. cedar) bedding material.
    3. Bedding must be changed when it is visibly wet.
  5. Social Behavior
    1. Animals should be group housed with same-sex conspecifics whenever possible.
    2. Group housed animals must be assessed for compatibility and separated if there is significant aggression. If animals are excluding others from food or water, additional feeders and waterers must be provided.
  6. Breeding
    1. Breeding must be justified on the animal use protocol.
    2. Standard breeding protocols should be followed. Attention should be paid to maintenance of genetic homogeneity (inbred animals) or heterogeneity (outbred animals). Genetic monitoring may be necessary for large or long-term breeding programs.
    3. Cage space requirements must be closely monitored for breeding animals. Because many laboratory mammals have large litters and rapid growth rates, usually no more than one breeding pair per cage is appropriate. Animals should be weaned before puberty and separated into same-sex groups based on adult maximum weights.
  7. Enrichment
    1. Animals require environmental enrichment to allow them to express normal specific behaviors.
    2. Enrichment can include group housing or other opportunities to socialize such as visual, tactile or olfactory contact with other animals, human interaction, exercise opportunities, nesting material, digging or chewing substrates, food enrichment or other activities that result in a positive psychological state for the animals.
    3. RAR's Animal Enrichment Program can be viewed here.
  8. Sanitation
    1. Methods
      1. Cages may be sanitized in a commercial cage washer with a soap wash and a high temperature (1800F) rinse. This service can be contracted with RAR.
      2. Cages may be hand washed with detergent, rinsed in water, then dipped in a sanitizing agent (1/2 oz bleach per gallon of water) and allowed to dry.
    2. Frequency
      1. Cages and waste pans should be sanitized weekly, or more often if required.
    3. Quality Control
      1. The efficacy of sanitation procedures should be monitored at least quarterly. This service is available through RAR.
        1. General procedures include bacteriological culture of cleaned equipment.

Food

  1. Type
    1. Animal food must supply all required nutrients unless the requirements of the study preclude it.
    2. Animals should be fed commercially available complete diets appropriate for their physiologic status.
    3. Rodents normally are fed a pelleted chow, which helps to wear down continuously erupting teeth. If powdered diets are to be fed a chewing substrate may be necessary, or tooth growth must be monitored.
  2. Amount
    1. Animals should be fed amounts of food to provide at least their maintenance requirements. The National Research Council publishes nutritional requirements for most animals. These are also available through RAR. [Nutrient requirements for laboratory animals; Dogs; Cats; Rabbits; Nonhuman Primates; Swine; Sheep; Poultry; Fish and Shrimp]
    2. If food is restricted for more than 8 hours for neonates, rabbits or rodents, 48 hours for ruminants, or 24 hours for other animals:
      1. For experimental reasons this must be approved by the IACUC, written criteria for assessing the animals’ body condition must be provided.
      2. For medical reasons this decision should be made with veterinary input.
  3. Quality Control
    1. Commercially prepared food must be used within 6 months of its milling date (usually printed on the bottom of the bag).
    2. Specially formulated diets may not have an expiration date. Generally these should be refrigerated and used within 6 months of manufacture.
    3. Quality control or nutritional analysis data should be obtained from the food manufacturer. If diets are prepared in-house, nutritional analysis should be performed following mixing and again at a later time point to determine the amount of degradation over time.
    4. Food should be stored in sealed, sanitizable containers. The type of food and expiration date should be marked on the container. Containers should be cleaned out weekly and sanitized monthly.
    5. Food should not be stored adjacent to animal waste containers or chemicals.
    6. Sterilized food should be stored in sterilized containers and the date of sterilization marked on the container.

Water

  1. Type
    1. For most purposes tap water from a potable water faucet is adequate for research mammals.
    2. For experimental reasons, animals may have special water requirements, such as a need for deionized water, for sterilized water, or for water treated with medications.
  2. Amount
    1. Generally, animals should have drinking water available at all times.
    2. If water is restricted for more than 24 hours for large animals, or 5 hours for rodents or rabbits:
      1. For experimental reasons this must be approved by the IACUC and objective, written criteria for assessing the animals’ hydration must be provided.
      2. For medical reasons this decision should be made with veterinary input.
  3. Quality Control
    1. For potable tap water, quality control beyond that which the municipality provides is not usually necessary.
    2. Special water needs may require additional monitoring. Water may need to be analyzed for chemicals or cultured for microorganisms.


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The information contained in this site is intended as a reference for University of Minnesota investigators, and animal husbandry and veterinary staff. Drug information and dosages are derived from a variety of sources and do not necessarily guarantee safety or efficacy. Information obtained through this site should not be relied upon as professional veterinary advice. Any medications administered or procedures performed on animals should only be performed by or under order of a qualified, licensed veterinarian.