How do you breed laboratory mice? - briefly
Breeding lab mice requires selecting genetically compatible breeding pairs, housing them in a sterile, temperature‑controlled cage with enrichment, and providing a balanced diet and ad libitum water. Offspring are weaned at three weeks, health‑screened, and recorded to preserve colony genetics.
How do you breed laboratory mice? - in detail
Breeding laboratory mice requires controlled genetics, standardized environment, and rigorous record‑keeping.
First, select the appropriate strain based on experimental goals. Verify health status through a certified pathogen‑free (SPF) program before introduction to the colony.
Housing must provide uniform temperature (20‑24 °C), humidity (30‑70 %), and a 12‑hour light cycle. Use individually ventilated cages (IVC) with bedding that minimizes allergens and supports nesting. Provide ad libitum access to autoclaved rodent chow and filtered water.
Establish breeding pairs according to age and reproductive status:
- Females: 8‑12 weeks old, proven fertility, regular estrous cycles.
- Males: 10‑14 weeks old, confirmed fertility, no signs of aggression.
Pair each female with a single male in a breeding cage. Maintain a ratio of one male to two or three females to reduce stress and maximize litter size.
Monitor mating by checking for copulatory plugs or vaginal cytology. Record the date of plug detection as gestation day 0. Gestation lasts approximately 19‑21 days.
During pregnancy, continue standard husbandry but avoid cage changes that could disturb the dam. Provide nesting material to promote comfortable nest building.
At birth, count pups and assess viability within the first 24 hours. Keep litters together with the dam until weaning at post‑natal day 21. Separate males and females at weaning to prevent uncontrolled breeding; assign each sex to designated cages with appropriate identifiers.
Maintain detailed logs for each animal, including:
- Strain and genotype.
- Birth date and litter size.
- Parent identifiers.
- Health observations and any interventions.
Implement regular health surveillance: fecal PCR for common pathogens, visual inspections for abnormal behavior, and periodic necropsies of sentinel animals.
Replace breeding pairs periodically to avoid age‑related fertility decline. Retire females after three successful litters or at 12 months of age; retire males after 12 months or upon detection of reduced mating performance.
By adhering to these procedures, colonies remain genetically stable, pathogen‑free, and capable of producing consistent experimental subjects.