Veterinary Clinical Services

Dystocia in Mice

• Initial assessment
• PI contact
• PI info for future reference
• PI/VCS decision
• Caesarian section and fostering

1. Initial assessment

• Have pups already been delivered? Live or dead?
• Is there a malpositioned pup currently stuck in the dam?
• Does cervix appear to be open?
• Can you palpate pups in the uterus?
• What is the condition of the dam?
  • Good = sleek, active, caring for/nursing pups
  • Bad = ruffled, dehydrated, dyspneic, prostrate, panting
• Has she had previous litters, or is she primiparous?

2. PI contact

Inform them that a mouse dystocia is a medical emergency and ascertain how valuable the dam and pups are to the PI.

• Dams rarely survive
• Pups may survive an immediate C-section followed by fostering
• If dam is in good shape
  • if  cervix is open, you can try 1-2 hours of drug treatment (oxytocin), especially if she has previously had successful litters so you know the plumbing works and she's a good mom.
  • Delaying the C-section increases the risk of losing the pups
  • Dam is still not a great prospect for future litters- she might have another dystocia (especially if this is her first litter)
• If dam is in bad shape
  • euthanasia/C-section (for important litter, with foster dam available)
  • euthanasia of dam and pups (unimportant litter, or mom in very bad shape and evidence that all the pups are dead)
• If a foster mom is available and the PI wants to try C-section
  • Best choice
  • Experienced dam
  • New litter (< 3 days, the younger the better. The older pups will outcompete the foster pups, though you may still have success if you remove the foster dam's litter.
  • -Different coat color (so you can tell them apart)
  • -NOT an important litter- there's a chance the foster mom will reject ALL the pups when you add the C-sectioned litter

3. PI info for future reference:

1. Provide nesting material- mice often fail to care for young if there is no nest.
2. Careful monitoring of founder mice near delivery time (check first thing every morning. Normal mice give birth only at night- if they are in labor during the day, something is wrong)
3. Co-parenting is an option for extremely valuable mice who are poor mothers. Founder female and female Swiss Webster are housed together, and both exposed to the founder male. They should have litters at about the same time. The SW will then be available as a foster if necessary, and may help with pup care, act as a calming influence on the founder female, and demonstrate pup care to the founder female. The cage density policy must be adhered to, but this can be addressed on a case-by-case basis.

4. PI/VCS decision

* Ca gluconate: 10% Ca gluconate (100 mg/ml) stock. A 30 gram mouse needs 3 mg, Make a 10 mg/ml solution (0.1 mls of 10% Ca gluc + 0.9 mls of saline or LRS), and use 0.3 mls of this solution for a 30 g mouse. Inject VERY carefully- don't hit the uterus.

** Oxytocin: 20 unit/ml stock solution. (Check for already made-up dilute solution, though). Make 2 unit/ml solution by diluting 0.1 mls oxytocin with 0.9 mls saline. Use 0.5 mls of this solution (mix well) for the first 1-unit dose, save the other 0.5 mls for re-dosing.

5. Caesarian section and fostering:

Supplies:

• heat lamp or exam lamp with 75 watt bulb
• hot water bottle 
• towel (put the towel over the bottle and under the lamp to make a nice warm nest
• gauze 4x4s
• small scissors, small forceps
• assistant

Procedure:

• Euthanize dam by cervical dislocation after metofane or CO₂ anesthesia
• Using scissors, make a small transverse snip in the skin over the abdomen, then peel the skin away cranially and caudally.
• Using the forceps and scissors, cut away the abdominal wall and exteriorize the uterus.
• Carefully cut off the ends of the uterine horns, and using gentle digital pressure, pop the pups out.
• Have the assistant gently remove the placenta and amniotic sac, wipe the mouth free of any obstruction, and stimulate breathing by rubbing the pup gently with the gauze.
• Keep the pups warm under the lamp, continue stroking them with the gauze.
• Splashing cold water on them (e.g. with a water bottle) may stimulate breathing (dry them immediately)
• Pups must be nicely pink, breathing actively, and moving around before fostering. If they don't provide the right response, the dam thinks they are dead and will cannibalize them.

Fostering:

• Depending on logistics, bring the pups to the foster dam or vice versa
• Minimize stress to the dam- remove her from the cage so she can't see what you are doing to her pups.
• Maximize olfactory clues that would fool dam into thinking the pups were hers
  • wear gloves when handling the pups
  • wipe the dam's urine on the pups
  • roll the new pups around with their foster siblings
  • cover the new pups with the foster nest material
  • overload the dam's sense of smell by putting a drop of vanilla or peppermint oil or perfumed lotion on her nose
• Remove and euthanize some of the foster pups so there are no more than a dozen pups for the foster mom. (Mice can't count- it doesn't need to be a 1-to-1 substitution)

If some of the foster mother's pups remain they need to be identifiable by (future) coat or eye color. If they have the same coat and eye color as the important pups, use tail or toe clips to mark the unimportant ones.

Send mail to Joan Bailie with questions or comments about this web site.
Copyright © 1999 Yale Animal Resources Center, Yale University
Last modified: February 13, 2000