How is milk collected from mice? - briefly
Lactating female mice are anesthetized, their nipples are gently massaged or pharmacologically stimulated, and the expressed milk is drawn with fine capillary tubes or a micropipette; collection is typically performed within a few hours after induction of lactation to maximize yield.
How is milk collected from mice? - in detail
Collecting lactational secretions from laboratory mice requires precise planning, controlled conditions, and adherence to animal‑care regulations. The process begins with selection of pregnant females that will become lactating dams. Breeding pairs are timed so that parturition occurs within a predictable window; the day of birth is recorded as day 0 of lactation.
Preparation of the dam
- Verify that the dam is healthy, free of mastitis, and has delivered a normal litter.
- Separate the litter from the mother for a brief period (typically 1–2 hours) to allow milk accumulation in the mammary glands.
- Maintain ambient temperature at 22–24 °C and provide soft bedding to reduce stress.
Induction of milk let‑down
- Administer a low dose of oxytocin (0.1–0.2 IU per mouse, intraperitoneally) 5–10 minutes before collection to stimulate involuntary contraction of myoepithelial cells.
- Ensure the animal is lightly anesthetized (e.g., isoflurane at 1–1.5 % in oxygen) to prevent movement while preserving physiological reflexes.
Collection technique
- Position the anesthetized dam on a warmed platform with the ventral side exposed.
- Identify the inguinal and abdominal mammary pads; gently massage each gland to express milk into a calibrated micro‑pipette or glass capillary.
- Collect 1–2 µL per gland, typically yielding 5–10 µL total per dam. If larger volumes are needed, repeat the separation‑let‑down cycle after a 4‑hour recovery period.
- Transfer the sample immediately into pre‑chilled microcentrifuge tubes containing protease inhibitors if downstream protein analysis is planned.
Post‑collection handling
- Return the dam to her cage and reunite with the litter promptly to minimize disruption of nursing behavior.
- Store milk samples on dry ice or at –80 °C; avoid repeated freeze‑thaw cycles.
- Record the exact time of collection, dam identification, litter size, and any deviations from the protocol.
Quality control
- Conduct visual inspection for contamination (e.g., blood, urine) and discard compromised samples.
- Measure protein concentration or specific markers (e.g., casein, whey proteins) to verify sample integrity.
- Maintain a log of all procedural variables to support reproducibility.
Following this systematic approach yields sufficient quantities of mouse milk for biochemical, immunological, or developmental studies while complying with ethical standards and ensuring data reliability.