Weaning mice

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Weaning mice
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Weaning mice

• Remove weaning-age mice (usually 21 days) from
  the parent cage.
• Separate the pups by sex.
• Mark the parent cage with a separation card mark
  the weaned cages with separation stickers

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Before you start

• Check the problem log to see if you expect to
  have any separations
• Check the room for green OC cards

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Before you start

• Check your watch!! What time is it?
• If you dont have a watch, check the time on your
  pager

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Why are you checking the time?

• So you can fill out the Special Services Log when
  you are done.

Date Principal Investigators Name Types of Service Cage Separation ( of cages) Types of Service Other Services Number of Hours Performed By (Print Name) Initials



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Before you start

• Double-check the OC card
• Is it a supervisor check?
• Double-check that the weaning due date is
  correct- look at the weaning date calendar.

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Weaning mice

• Remove weaning-age mice (usually 21 days) from
  the parent cage.
• Separate the pups by sex.
• Complete the necessary paperwork

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Can you tell sex by color?
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Can you tell sex from how theyre dressed?
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We determine the sex of mice by examining the
genitals
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It isnt so easy to sex pups
Female
Male
Female

• For pups, the ano-genital distance is used to
  determine sex.

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The ano-genital distance is longer in males than
in females
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• Female pups have a shorter anogenital distance
• Female pups have nipples (which may not be
  visible if the pups are furry)

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What sex is this pup?
l
l
Male Female
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Sex pups 2 at a time

• If they look the same, try again until you get
  one that looks different.
• The one with the longer anogenital distance is
  the male. The other is the female.
• Keep one pup of known sex, and use it to compare
  against the rest of the pups.

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What sex is this pup?
Female Male
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What sex is this pup?
Female Male
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Male Female
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Male Female
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Female Male
l
l
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Weaning set-up

• Parent cage
• Male pup cage
• Female pup cage
• Even if you have more than 10 pups, start by
  separating the pups by sex into two cages.

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Put some food on the floor for the pups
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Housing pups

• 5 females per cage
• 4 males per cage
• Recheck the sex
• Put pellets of food on the cage floor
• Complete the green separation cards and stickers
• House the separated cages on the separation shelf

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Separation cards

• The white sticker (with the separation number)
  goes on the green card.
• Write the date and the number of new cages
  created on the white sticker

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• Write the separation number on
• The white cage card
• Each of the green separation stickers

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Put the separated cages on the separation shelf
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Before you finish

• Update the census
• Initial the addressed column in the problem log
• Fill out the Special Services Log.

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Update the census

• Write the number of new cages created in the plus
  () column of the census.

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Initial the addressed column in the problem log
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Fill out the Special Services Log.

• Fill out the Log. Put the number of new cages
  created in the separation column.
• Look at your watch to determine the time to
  complete the separation. The whole time
  (including paperwork) counts.

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The end