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Written by Super User. Posted in Animals

Name Mlac:WR and Mlac:SD
Sciencetific Name Rattus  norvegicus
Strain Wistar and Sprague Dawley
Source Denmark
Coat color Albino
Biological Data  
Adult body weight 

Male 250-300 grams,Female  180-220 grams

Average life span 2-3 years
Age at mating

Male 8-10 weeks, Female 8-10 weeks

Estrous cycle  4-5 days
Duration of estrus 9-20 hours
Gestation period  19-22 days
Weaning age  19-22 days
Litter size 9-11 pups
Normal birth weight  5-6 grams
Weaning weight 45-65 grams
Food consumption  15-30 grams /animal/day (Adult)
Water consumption 

20-45 ml/animal/day (Adult)

Eyes open 10-14 days
Ears open 12-14 days
Hair coat 8-9 days
Nipples 10, 3 Pairs on the thorax, 2 Pairs on the abdomen.
Growth rate  


Breeding Systems

Maximum avoidance of inbreeding mating system is applied in Mlac:WR and Mlac:SD rats strains for maintenance in foundation stock and random mating system is used for production in production stock.


The rats are housed in controlled environment. The ventilation, temperature and humidity are controlled by HVAC (Heating, Ventilating, Air conditioning) system. They are controlled at : 

- 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

The rat are sensitive to noise so the noise level should be maintained less than 85 db.

Feed and water

           The rats are fed on commercial diet (No. CP 082) produced by Perfect companion group co. Ltd. The manufacturer which milled the feed according to our requested specifications. Food is provided ad libitum in stainless steel wire- bar lid feeders. The chlorinated RO Water is provided as drinking water (chlorine concentration 5-6 ppm) which is  free from Pseudomonas aeruginosa. Water provided to animals by bottles with sipper tubes.


 Dried Water Hyacine and Corn Cob used for mice as bedding material. The same bedding is used in shipping containers. Dried bedding is packed in 3 layers brown paper bags and sterilized by autoclave at 135 C for 7 minutes before used.


Various sized of cages are used in different purpose of breeding process.

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

Maximum Number Animals/Enclosure

Types of Enclosure & Description

12 × 11 × 7.5

3 animals(pregnant 1wk) /cage

Stainless steel cages with Stainless steel wire-bar lid

10 × 7 × 10

1 animal(pregnant 2-3  wks) /cage

Stainless steel cages with Stainless steel wire-bar lid

10.5 × 13.5× 6.5 1 Female + litter /cage Polycarbonate cages with Stainless steel wire-bar lid
10 × 16× 7 1 Female + litter /cage Stainless steel cages with Stainless steel wire-bar lid
14 × 29× 6 10 animals /cage Stainless steel cages with Stainless steel wire-bar lid