Colony management is a fundamental pillar for ensuring stable and productive breeding output. Have you ever been troubled by poor breeding performance in your rats and mice? Let's explore and summarize the breeding issues commonly encountered with rodents, and say goodbye to the woes of rodent reproduction!
 

1. Strict Breeding Stock Selection Criteria

As the first and crucial step towards successful rodent breeding, we must pay close attention to the selection process. Keep these principles for selecting future breeding stock firmly in mind:

● Whether for inbred or outbred strains, potential breeders are generally selected starting at 3 weeks of age.

● Animals from the 2nd to 5th litters are preferred for breeding stock.

● Consider the strain's typical litter size. Select from litters that had appropriate male-to-female ratios and litter sizes.

● For inbred strains: Select littermate (brother-sister) pairs for breeding.

● For outbred/closed colonies: Select only one male OR one female per litter, following the standard A, B, C breeding rotation principles for outbred stocks.

Physical examination during the selection process is also critical. Do not select animals with conditions like cataracts, vaginal septum, cryptorchidism, etc. Offspring from mothers with a history of cannibalism should also generally be avoided for breeding.

 

2. Appropriate Housing Conditions

Suitable housing is another key factor for stable colony productivity. Provide rodents with an appropriate and stable environment regarding temperature, humidity, and a quiet setting.

● Determine cage stocking density and group composition based on the available cage floor area and animal welfare guidelines.

● Change bedding regularly.

● Ensure ad libitum access to fresh feed and water.

● Maintain strict entry protocols for personnel and supplies to uphold a stable microbiological status (e.g., SPF).

● Implement appropriate work and light/dark cycle schedules, ensuring ambient light levels are suitable.

 

3. Standardized Breeding Procedures

● Initiate breeding at the appropriate age. Conventional strains are typically bred starting at 8 weeks for mice and 10 weeks for rats.

● Based on cage size and strain characteristics, common breeding setups are 1 male with 2 females or 1 male with 1 female.

● Before co-housing, re-check the animals' physical appearance and cage/card information for accuracy.

● Cages may not need bedding changes during the first 2 weeks of co-housing. After 2 weeks, change bedding weekly.

● For conventional strains, if no litter is produced after 4 weeks of co-housing, the pair/trio can usually be retired. However, breeding capacity varies between strains, different disease models, or specific genetically engineered models. The decision to extend the co-housing period before retirement should be made based on the known characteristics of the specific strain/model.

 

● Accurately record the birth date of new litters.

● Avoid cage changes or other husbandry procedures for 3-5 days after birth to prevent maternal stress, which can lead to cannibalism or rejection of pups.

● Weaning is typically performed at 3 weeks of age. Weaning too early can affect pup survival and growth rates. Weaning too late may lead to overlapping litters, reducing survival of the new litter or triggering cannibalism, thus impacting productivity.During weaning, take care not to miss any pups. Crucially, do not accidentally remove a breeding adult.

 

Daily Operations: Prioritize Animal Welfare and Biosecurity

Securely close cage lids to prevent escapes.

Maintain detailed and standardized record-keeping on cage cards.

After weaning, pay attention to animal density, provide food and water promptly, and separate males and females in a timely manner.

Do not place items that have contacted animals or clean supplies on the floor.

Promptly report and cull animals with abnormal appearance or escapees.
 

 

Following this discussion, assess your own rodent colony to see if any improvements are needed in your management practices.

 

Special Statement: This article is from the official WeChat account of MingCeler Biotech. Personal sharing is welcome. Media or institutions are prohibited from reprinting to other platforms without authorization. For reprint permission or other inquiries, please contact us via the official account backend or at sales@mingceler.com.

Disclaimer: Some materials are sourced from the internet. Contact us for removal if infringement is found. This article is for informational purposes only. The views expressed do not represent the official stance of MingCeler Biotech. This article does not constitute treatment recommendations. For treatment guidance, please consult a qualified healthcare professional.