Weigh-Suckle-Weigh Milk Volume Measurement

Weigh-Suckle-Weigh Protocol at PND10.5

• This is usually done at PND10.5 (Usually denote PND0.5 as the day pups were born).
• Weigh dam alone using the regular metric weighing scale (in the procedure room) and weigh aggregate of pups by placing all pups on weighing paper using the analytical scale (in the lab).
• Keep the dam in the original cage with food and water bottle ad-lib. Place pups in a new cage without food or water, but keep the normal cage enrichment (the bedding pouch, tear it open, and put it on top of pups as a blanket).
• Put the pup cage on a heating pad (set heat to “high”) so they will remain warm for the separation period. Put ¾ of the cage on the pad and leave a ¼ on the silver bench so pups can choose to move around if they get too warm. I usually place the dam’s cage next to the pups with the similar ¾ ¼ alignment on the heating pad and bench, respectively.
• Keep the pups and dam separated for two hours.
• After two hours of separation, weigh the pup aggregate weight on the analytical scale and weigh the dam using the metric weighing scale.
• Recombine the pups and dam in the original cage.
• After one hour of nursing, weigh the dam again using the metric weighing scale then weigh the aggregate of pups using the analytical scale.

Note 1:

• The data collected should look something like this for the dam and pups for all time points. This is an example to highlight the 3 data points for weight measurements.

Dam wt 26.9g ---> after 2 hour separation 25.7g ---> after 1 hour nursing 25.0 Pups wt 22.71 ---> after 2 hour separation 22.55 ---> after 2 hours nursing 23.20g

Note 2:

• The weight of the dam may decrease after 2-hour separation from pups, do not worry about that (despite assuming the dam should retain more milk and gain weight).