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Written by Super User. Posted in Animals

Name Mlac:ICR
Sciencetific Name Mus  musculus
Strain ICR
Source Japan (1980)
Coat color Albino
Biological Data  
Adult body weight 

Male 25-40 grams,Female  20-35 grams

Average life span 2-2.5years
Age at mating

Male 6-8 weeks (25-40 grams) , Female 6-8 week. (25-35 grams)

Estrous cycle  4-5 days
Duration of estrus 10 hours
Reproductive time 8-9 months
Gestation period  19-21 days
Weaning age  18-21 days (10-14 grams)
Litter size 1-1.5 pups (average 4)
Normal birth weight  1-1.5 grams
Post partum estrus - NO -
Food consumption  3-6 grams /animal/day (Adult)
Water consumption 

3-8 ml/animal/day (Adult)

Nipples 10, 3 Pairs on the thorax, 2 Pairs on the abdomen.
Eyes open 12 days
Growth rate



Breeding Systems

Maximum avoidence of inbreeding is used for stock maintenance system infoundation stock and random mating system is used for production in production stock.


The Mlac:ICR is housed in controlled environment. The ventilation, temperature and humidity are controlled by HVAC (Heating, Ventilating, Air conditioning) system.  

- Temperature range is controlled at about 22 ± 2 ํ 

- Relative humidity range at about 55 + 10%

- Air changes per hour at 15-20 ACH

- Light: dark cycle is adjusted at 12:12 hours

- Mouse are sensitive to noise so the noise level should be maintained at< 85 db.

Feed and water

           The Mlac:ICR is fed on the commercial diet (No. 082) product of Perfect companion group co. Ltd., the animal feed manufacturer which milled according to our requested specifications. Food is provided in stainless steel wire- bar lid feeders ad libitum. The RO Water is used for the drinking water which is chlorinated at a concentration of 5-6 ppm to make it free from Pseudomonas aeruginosa. The drinking water is provided in bottles with sipper tubes.


 Dried water hyacinth and corn cob are is used for mouse as bedding material. The same bedding is used in shipping containers. Dried bedding is packed in 3 Layers paper bags and sterilized by autoclave at 135 ํC   for 7 minutes before used.


Different size of cages are used in different breeding processes as follows.

Dimensions of Enclosure (W×L×H)(centimeter)

Maximum Number Animals/Enclosure

Types of Enclosure & Description

7.5 × 11.5 × 5

6 animals/cage (or) 1 animal (lactating female)/cage

Polysulfonate and stainless steel cages with stainless steel wire-bar lids

11 × 18× 6

4 Female + litter (lactating female)/cage

Stainless steel shoe box type with stainless wire-bar lid

14 × 29× 6 8 Female + litter (lactating female)/cage Stainless steel shoe box type with stainless wire-bar lid
14 × 29× 6 35 animals(5-8 weeks)/cage
50 animals(3-4 weeks)/cage
Stainless steel shoe box type with stainless wire-bar lid


Space requirement for Mlac:ICR

Weight, g.

Floor Area/Animal,(in2)


Under 10



Up to 15 8 5
Up to 25 12 5
Over 25 At least 15 5