Methods for collecting milk from mice

Abstract

Mouse models offer unique opportunities to study mammary gland biology and lactation. Phenotypes within the mammary glands, especially those caused by genetic modification, often arise during lactation, and their study requires the collection of adequate volumes of milk. We describe two approaches for collecting milk from lactating mice. Both methods are inexpensive, are easy to use in the laboratory or classroom, are non-invasive, and yield adequate volumes of milk for subsequent analyses.

Figure 1

Mouse milking procedures. a Method 1 showing milk being drawn into the Pasteur pipette from the right thoracic #3 mammary gland. b Mouse being milked using Method 2. The soft latex tubing is positioned over the teat, with milk being collected into the collection tube. c Apparatus used in Method 2. A Tygon tubing connected to house vacuum, progressively stepped down in size, B roller clamp, C rubber stopper connected to tubing via connector, and bored to receive the 1.5 ml centrifuge tube, D Multiflex tip penetrating rubber stopper, E latex teat cup, F 1.5 ml centrifuge tube. The dark blue clamp (bottom center) is an optional vacuum cut-off. d Coomassie blue-stained SDS-PAGE analysis of milks from different species and their crude fractions, as prepared by undergraduate students. The predicted proteins detected in mouse milk (as described by Boumahrou et al. [2]) are 1. whey acidic protein, 2. γ-casein, 3. β-casein, 4. αs1-casein, 5. serum albumin, 6. lactoferrin.