How can you milk mice? - briefly
By using a precise micro‑surgical technique to expose the lactating mammary glands of anesthetized female mice, applying gentle suction with a calibrated capillary system, and collecting the secreted fluid into sterile micro‑tubes. The process demands sterile conditions, careful temperature control, and immediate analysis of the harvested milk.
How can you milk mice? - in detail
Extracting milk from laboratory rodents requires precise physiological manipulation, sterile equipment, and strict adherence to animal‑care regulations. The process begins with selecting appropriate subjects: adult female mice that have recently given birth and are actively lactating. Hormonal status can be enhanced by administering oxytocin (0.5–1 IU intraperitoneally) shortly before collection to promote milk let‑down.
The animal is anesthetized using an inhalation agent such as isoflurane (1.5–2 % in oxygen) to minimize stress and movement. Once the depth of anesthesia is confirmed, the ventral abdomen is cleaned with an antiseptic solution and a sterile drape is placed to maintain a clean field.
Milk extraction proceeds as follows:
- Place a warmed, sterilized glass capillary tube or micro‑pipette tip against each exposed nipple.
- Apply gentle, rhythmic suction using a calibrated syringe or a low‑pressure vacuum pump (approximately 10–15 mm Hg).
- Collect the expelled fluid into pre‑cooled microcentrifuge tubes kept on ice.
- Rotate the animal gently to access all mammary glands, repeating steps 1–3 for each pair of nipples.
After collection, the animal is allowed to recover in a temperature‑controlled cage and monitored until normal respiration resumes. The milk samples are centrifuged at 4 °C (1,500 g for 10 minutes) to separate fat globules, then aliquoted and stored at –80 °C for downstream analysis.
Key considerations include:
- Maintaining aseptic conditions throughout to prevent bacterial contamination.
- Limiting the total volume harvested per session (typically ≤ 50 µL per mouse) to avoid compromising the dam’s nutritional status.
- Recording the exact time post‑parturition, as milk composition varies markedly during the first two weeks of lactation.
- Securing institutional animal‑care committee approval and following the Guide for the Care and Use of Laboratory Animals.
By integrating controlled anesthesia, oxytocin‑induced let‑down, and precise suction techniques, researchers can reliably obtain murine milk for biochemical, immunological, or developmental studies while ensuring animal welfare.