Space Recommendations

BACKGROUND

The Guide for the Care and Use of Laboratory Animals (the Guide, NRC 2011) lists the minimum space recommendations for laboratory animals. Some of the issues addressed are as follows: "Singly housed animals may require more space per animal than that recommended for group-housed animals, while larger groups may be housed at slightly higher densities." (p.58) "When selecting a suitable social environment, attention should be given to whether the animals are naturally territorial or communal and whether they should be housed singly, in pairs, or in groups. An understanding of species-typical natural social behavior (e.g., natural social composition, population density, ability to disperse, familiarity, and social ranking) is key to successful social housing." (p.64) Population density can affect reproduction, metabolism, immune responses and behavior. Group composition should be held as stable as possible as mixing groups or introducing new members can alter behavioral and physiological functions. Larger animals may require more space to meet the performance standards.

The Guidance on Prompt Reporting to OLAW under the PHS Policy on Humane Care and Use of Laboratory Animals (PHS/OLAW NOT-OD-05-034) states as an example of reportable situtions the following: "Chronic failure to provide space for animals in accordance with recommendations of the Guide unless the IACUC has approved a protocol-specific deviation from the Guide based on written scientific justification."

IACUC Policy

Compliance with the following guidelines is required unless written exception has been approved by the Wayne State University Institutional Animal Care and Use Committee (IACUC) on the grounds of accomplishing scientific objectives. Divergences from this policy should be discussed with the veterinary staff. NOTE: For animals that are not listed below, contact a veterinarian.

Table 1. Recommended Minimum Space for Mice and Rats Housed in Groups (the Guide, p. 57)

Animal Weight (g) Floor Area/Animal (in2) Height (in)
Mice <10

6

5

10 - 15 8
15 - 25 12
>25 ≥15
Female + litter 51
Rats <100 17 7
100 - 200 23
200 - 300 29
300 - 400 40
400 - 500 60
>500 ≥70
Female + litter 124

 

Table 2. For standard caging used by DLAR – these recommendations translate into the following examples

Animal/Cage Type Cage Size (in2)* Maximum Number of Animals

Small mouse static

microinsolator cage

60 5 mice <25g
4 adult mice ≥25g
2 adults with unweaned litter
Small mouse ventilated cage 75 6 mice <25g
5 mice ≥25g
2 adults with one unweaned litter
Large mouse static 144 12 mice <25g
Animal/Cage Type Cage Size (in2)  Maximum Number of Animals

microisolator cage and

Large mouse ventilated cage:

Allentown (Purple)

140 9 mice ≥25g
3 adults with two unweaned litters**
Rat microisolator 144 6 rats <200g
5 rats <300g
3 rats <400g
2 rats ≥400g
2 adults with one unweaned litter
Rat ventilated cage 140 6 rats <200g
5 rats <300g
3 rats <400g
2 rats ≥400g
2 adults with one unweaned litter
Suspended wire/metabolism cage 66 1 rat <500g

*Cage size determined by measuring length and width of a cage at the level of the surface of the bedding.

**A breeding trio consists of 3 adults (1 male and up to 2 females with nursing litters)

 

Table 3. Space recommendations for other rodents (the Guide, p. 57)

Animal Weight (kg) Floor Area/Animal (ft2) Height DLAR Enclosure Area (ft2) Max # of Animals/DLAR Enclosure
Guinea Pigs <350 60 7 202 3
≥350 ≥101   2

 

Table 4. Space recommendations for rabbits (the Guide, p. 59)

Animal (Rabbits) Weight (kg) Floor Area/Animal (ft2) Height (in) DLAR Enclosure Area (ft2) Max # of Animals/DLAR Enclosure
Allentown standard cage <2 1.5 16 5 ft2 3
2 - 4 3 1
4 - 5.4 4 1
>5.4 ≥5 1
Allentown extended cage <2 1.5 16 10 ft2 6
2 - 4 3 3
4 - 5.4  4 2
>5.4 ≥5 2
Alternative design standard cage <2 1.5 16 6 ft2 4
2 - 4 3 2
4 - 5.4 4 1
>5.4 ≥5 1
Alternative Design expanded cage <2 1.5 16 12 ft2 8
2 - 4 3 4
4 - 5.4 4 3
>5.4 ≥5 2

 

Table 5. Space recommendations for other animals (the Guide, p. 59, 62)

Animal Weight (kg) Floor Area/Animal (ft2) Height (in) DLAR Enclosure Area (ft2) Max # of Animals/DLAR Enclosure
Cats ≤4 3 24 3' x 1.8' , 5.5 1
>4 ≥4
Dogs <15 8 Able to stand erect 6' x 4' , 24 3
15 - 30  12 2
>30 ≥24 1

Swine

1/enclosure

15 - 100 varies Able to stand erect

a) 6' x 4' , 24 

b) 2 adjacent contiguous pens, 48

1
100 - 200 48 1 swine in 2 contiguous pens
>200 ≥52     Not allowed

Sheep and Goats

1/enclosure

<25 10 Able to stand erect

a) 6' x 4' , 24

b) 2 adjacent contiguous pens, 48

4
25 - 50 15 3
>50 ≥20 2

Sheep and Goats

2-5/enclosure

<25 8.5 Able to stand erect

a) 6' x 4' , 24

b) 2 adjacent contiguous pens, 48

5
25 - 50 12.5 3
>50 ≥17 2

 

Table 6. Space recommendations for aquatic species (the Guide, p. 83)

Animal Weight (kg) DLAR Enclosure/water requirements Max # of animals/DLAR Enclosure
Zebrafish* NA

5 adult fish per L water

20 eggs or larvae per 100 mL

Varies

*Matthews M, Trevarrow B, Matthews J. 2002. A virtual tour of the guide for zebrafish users. Lab Anim 31:34-40.

 

Approved: December 2012

Revisions Approved: 3/2013, 6/2013, 9/2015, 4/2016, 6/2018