The overall goal of this procedure is to demonstrate how to collect milk from a mouse or reeve's mutt jack deer for use in a variety of scientific experiments. This is accomplished by first administering oxytocin to the animal to stimulate the letdown of milk, then the animal is anesthetized. Next one, researcher manually expresses the milk while a second researcher collects it.
The final step is to ensure safety of the animal as she recovers from anesthesia. Ultimately, one can collect approximately five to 30 milliliters of mutt jack milk per session, or up to 450 microliters of mouse milk per session. The main advantage of this technique over existing methods, such as those that require specialized equipment, is that this technique is relatively inexpensive and Easy to learn.
This method can help to answer several scientific questions such as whether a pathogen can be passed from mother to offspring via milk. Individuals that are new to this method will generally get discouraged because it takes practice to properly express the milk. Assisting me with this procedure will be Stephanie full away, a technician from our laboratory To stimulate the release of milk in a lactating mouse.
Administer two international units per kilogram of oxytocin intraperitoneal immediately before collecting the milk, anesthetize the mouse and apply a small amount of eye lubricant to each eye to prevent the mouse's eyes from drying out while waiting for the anesthetic to take effect. Prepare some sterile alcohol prep pads, a P 200 pipette man, sterile pipette tips, and a container to hold the milk such as a 1.5 milliliter einor tube, or a 1.2 milliliter cryo vial. The milking requires two researchers.
One, the milk expressor stabilizes the animal and expresses the milk the other. The milk collector collects the milk being careful to avoid contaminating the collection vessel. Using a sterile alcohol prep pad, the milk expressor gently cleans the mammary area prior to milking.
Within a minute or two of the oxytocin injection milk letdown becomes visible in the mouse's mammary area. Manually express milk from the tet by using the thumb and forefinger to gently massage and squeeze the mammary tissue in an upward motion until a visible bead of milk begins to form at the base of the Tet. The milk collector now presses the P 200 pipette man plunger to its first stop to release air out of the pipette tip and to prepare for milk collection.
Then the milk collector positions the pipette tip at the top of the drop of milk. Being careful not to put the tip too close to the tet or the skin and slowly releases the pressure on the plunger to pull the milk into the pipette tip, pressing the pipette tip against the side of the collection tube so that no liquid is lost. The milk collector uses the thumb to press the plunger past the first stop and expel the milk into the container.
Continue to manually express milk from each teat moving in either a clockwise or counterclockwise direction. It is acceptable to return to a previous teat to express more milk, especially if it produces more milk than other teats. When finished collecting milk, allow the mouse to wake up from the anesthesia.
Once the dam is moving easily about the cage, place her back into her original cage with her litter to stimulate milk letdown. In lactating reeve's mut jack deer administer 10 international units per kilogram of oxytocin, intramuscularly then immediately anesthetize the mutt jack. The level of anesthesia is deemed adequate if there are only minor reflexes upon touching the ears, and if the milk expressor can hold the mut jack without struggle.
Next, apply a small amount of lubricant to each eye to prevent the mut jack's eyes from drying out. Equip both the milk expressor and the milk collector with ethanol soaked gauze and several 15 milliliter conical polypropylene tubes to hold the milk. As the oxytocin begins to take effect, milk letdown becomes visible in the mutt jacks mammary area.
Both the milk expressor and the milk collector should wear gloves and sanitize them with ethanol soaked gauze. Also use ethanol soaked gauze to sanitize the entire utter and each individual tet of the animal holding the munch jack's head in a comfortable position to allow ease of breathing and prevent rumen regurgitation. The milk collector places the collection tube close to the tet being milked without touching it to the skin.
The milk expressor uses the thumb and forefinger to gently squeeze the mammary tissue in an upward motion until the tet is engorged with milk and then gently rolls the milk out of the tet and into the tube that the milk collector is holding. The milk comes out in a stream, so it is important that the collection tube is positioned so that little milk is wasted. The Mt Jack's utter is divided into quadrants.
The milk expressor continues to express milk from each quadrant until the milk no longer flows easily. If milk cannot be expressed from one teat expressed from all other teats before returning to the first, when finished collecting milk, administer aamaz subcutaneously for rapid reversal of the bam anesthesia, finally monitor the dough until she is able to walk, eat, and drink on her own. This figure indicates that 100 to 450 microliters of milk can be obtained from a lactating mouse.
The maximum milk volumes were harvested eight to 12 days post partion using two international units per kilogram of oxytocin. Shown here is the approximate milk yield from a lactating mouse plotted according to litter size in reeve's mut jack deer. The volume of milk collected per session ranged from five to 30 milliliters depending on the anesthetic used and the time post partion milk collections start and finish dates for the mut, Jack dams are shown in this table.
Milk was collected an average of 80 days with a range from 18 to 150 days Once mastered, this technique can be performed in about one hour, depending on how many animals you'd like to collect from in one session. While attempting this procedure, it's always important to remember the safety of the animals comes first. Following this procedure, processing the milk may be necessary, followed by in vitro testing or bioassays, which may help to answer additional questions about components in the milk.
