Introducing new female mice into established colony

Snakefood · 01-17-12, 03:07 PM

I have already put them in a tank with old bedding from the colony so they will smell somewhat like the colony I wish to introduce them into. I have also introduced the male to them with no problems (DUH!)

What I am wondering is when do I put them with the females in the colony? one female has a litter (almost 1 wk old) and the other looks like she should have popped days ago, so any time she'll have newborns.

I NEED these litters to grow to maturity, I don't want to bother the new mothers into killing thier litters because I put new females in.

What do you guys think, will they be ok, even with the small babies?? Or should I wait until the litters are older??

mykee · 01-17-12, 03:12 PM

I never introduce new animals into an already existing colony. Start a second colony with the newbies. Mice form bonds very quickly and rarely even accept new members in.

stephanbakir · 01-17-12, 03:15 PM

did you first quarantine the new female before introducing her to your male?

Thats the biggest thing.

exwizard · 01-17-12, 03:17 PM

Our mouse colonies are nothing more than 1.6 breeding groups. One group in each lab cage is one colony. None of the mice EVER get mixed in with other colonies and right now, we have 9 of these going plus 3 lab cages for growouts. Those are the only mice that ever get mixed together.

Snakefood · 01-17-12, 03:29 PM

Quote:

Originally Posted by stephanbakir

did you first quarantine the new female before introducing her to your male?

Thats the biggest thing.

yes, they were properly quarantined before introducing the male to them.

So If I can't introduce new ones, how do I build the first one up to better #'s?? Do I leave the female offspring in there for the #'s I want?? If so, won't they get pregnant too soon/young?? and also being impregnated by thier father??

I know alot of people say in-breeding in rodents doesn't matter and actually strengthens lines. However, I noticed in my rat colonies (my past ones) that once you got 3 generations on, litter #'s went down, mortality #'s went up and mothers sarted dying pregnant. So I tend to be more careful these days about the bloodlines in my colonies (both rat and now mouse)

stephanbakir · 01-17-12, 03:32 PM

Quote:

Originally Posted by Snakefood

yes, they were properly quarantined before introducing the male to them.

So If I can't introduce new ones, how do I build the first one up to better #'s?? Do I leave the female offspring in there for the #'s I want?? If so, won't they get pregnant too soon/young?? and also being impregnated by thier father??

I know alot of people say in-breeding in rodents doesn't matter and actually strengthens lines. However, I noticed in my rat colonies (my past ones) that once you got 3 generations on, litter #'s went down, mortality #'s went up and mothers sarted dying pregnant. So I tend to be more careful these days about the bloodlines in my colonies (both rat and now mouse)

If you can, introduce new blood into the colonies. If you cant then let the females get old enough to safely breed and introduce them in with the new male.

exwizard · 01-17-12, 03:35 PM

Our rat wholesalers do it differently than we do. They start an entire colony run them through the breeding process and retire them all at the same time. They never mix their colonies together. When the females get pregnant they get pulled to a cage by themselves maked with their colony # to nurse and wean. Then they are returned to THAT colony to breed again. They have multiple rat colonies totalling over 14,000 rats and they've done quite well.

KORBIN5895 · 01-17-12, 05:36 PM

I just introduced 8 new females with only one having any problems with the others. She had problems with the others at the pet store too. She got chewed pretty bad and I put her down. The other 7 are aokay and two are pregnant.

exwizard · 01-17-12, 05:43 PM

I think thats awesome. Mice are funny like that.

KORBIN5895 · 01-17-12, 06:27 PM

I should also mention my mice are in a 4'x2'x3' deep freezer and the females that are nursing or about to give birth are in the same enclosure but are segregated under a domed metal cage top from an a small rodent cage. Similar to this but all black metal

Snakefood · 01-17-12, 07:14 PM

right now my colony is in a 33 gal tank, my other one will be in a 25 gal short (same floor space as a 33 gal but much shorter). However, hubby is almost finished my rat rack and will start on a rack system for my mice then, so this is temporary.

exwizard · 01-17-12, 07:40 PM

yeah a rack system is definitely the way to go with this. Its much easier to clean and takes up much less floor space. Id be interested to see what these racks look like.

Laura's mother, who also built the rat racks we're currently using, is working on a design for the mice. In the meantime, we're using lab cages in a shelving unit.

KORBIN5895 · 01-17-12, 07:45 PM

My mice are in an unheated shed. So I need the deep freeze to keep the warm. I use a 100 watt red bulb attached to a regular house thermostat to heat it.

exwizard · 01-17-12, 07:55 PM

Its good that youre taking this precaution in the Winter. Ours are in the basement. Its usually pretty warm down there... good thing considering it will get down to 10 tonight and stay cold all week.

KORBIN5895 · 01-17-12, 08:21 PM

The thermostat is a must as I baked 5 of them the first night I had it on :/