How do you properly breed mice? - briefly
Choose disease‑free, genetically compatible males and females, house them in a temperature‑controlled cage with nesting material, a 12‑hour light cycle, and provide a balanced diet and water ad libitum. Separate the female before parturition to prevent cannibalism and record mating dates and litter sizes for future colony management.
How do you properly breed mice? - in detail
Effective rodent breeding requires a systematic approach that addresses genetics, environment, nutrition, and health monitoring. Begin by defining the breeding objective—whether to maintain a stable colony, produce a specific genotype, or generate experimental cohorts. Select breeding pairs that meet the genetic criteria and exhibit robust health, avoiding individuals with known defects or excessive inbreeding coefficients.
Housing should provide ample space, nesting material, and a stable microclimate. Standard cages equipped with a ventilated rack system maintain temperature at 20‑24 °C and relative humidity between 40‑60 %. Provide a 12‑hour light/dark cycle and ensure cages are cleaned weekly to reduce pathogen load.
Nutrition must be consistent and nutritionally complete. Offer a pelleted diet formulated for laboratory rodents, supplemented with fresh water ad libitum. During gestation and lactation, increase caloric density by 10‑15 % to support fetal development and milk production.
Mating protocol:
- Pair a proven male with one or two females; avoid overcrowding.
- Introduce the male during the early dark phase when mice are most active.
- Observe for copulatory plugs within 24 hours; presence indicates successful mating.
- Record the date of plug detection as embryonic day 0.5.
Gestation lasts approximately 19‑21 days. Monitor pregnant females for weight gain, nesting behavior, and signs of distress. Provide additional nesting material and a quiet environment during the final week.
Birth and early care:
- Expect a litter of 5‑8 pups. Count and sex the offspring within 24 hours.
- Keep the dam with the litter; avoid handling pups before postnatal day 3 to reduce stress.
- Maintain cage temperature at 28‑30 °C for the first week to prevent hypothermia.
Weaning occurs at postnatal day 21. Separate males and females to prevent premature breeding, unless intentional. Transfer weaned mice to clean cages with standard bedding and continue the same diet.
Record-keeping is essential. Document parental IDs, mating dates, litter size, sex ratios, and any health observations. Use this data to calculate breeding efficiency metrics such as litter size average, weaning success rate, and generation turnover time.
Health surveillance includes routine health checks, fecal parasite screening, and serological testing for common rodent pathogens. Implement quarantine for new arrivals and maintain strict biosecurity protocols to prevent disease introduction.
By adhering to these practices, colonies can be maintained with predictable genetic outcomes, high reproductive performance, and minimal health complications.