# Deliberately delaying pregnancy just to scare me..



## SarahY (Nov 6, 2008)

..or so it seems.

Five weeks ago I paired up an ivory satin Abyssinian with my sepia satin Abyssinian buck, with the aim of producing more ivories to work with. This would be her second litter, she'd been resting about two months since weaning her first litter. Two weeks and one day later the ivory doe had just started developing a little round potbelly, so three days after that I put her in her own cage to get settled in and kindle. That was two and half weeks ago. Since then she has been slowly getting bigger and bigger until she was the biggest mouse I had ever seen! Every day for two weeks I've been saying to myself "it's got to be tonight, surely?" but no.

Finally, last night, I had to clean out her substrate around her as she was just too big to lift safely. I looked down at her in her cage and said, firmly but kindly, that if she didn't have her babies in the next 24 hours I would have to cull her - I was afraid something had gone seriously wrong and she was starting to have trouble moving about.

This evening I have a litter of healthy, normal looking, squiggly pinkies with big bellies full of milk and a normal looking mum!

This ever happened to anyone else? I've heard of delayed _implantation_, but delayed _birthing_ is new one for me. She looked ready to kindle at three weeks - but evidently she just decided she'd wait another two!

Sarah xxx


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## WillowDragon (Jan 7, 2009)

This has happened to me twice... the first time with a PEW doe that literally looked like she was going to pop for a week and a half, at one point she couldn't move. I ended up doing the same as you... giving her til tomorrow before I culled her, the next day I went in and there were the babies! lol
The second time was with a doe from my lilac lines TWO FRIGGING WEEKS, to the point that i couldn't touch her, i was so scared to move her, again, made the decision to cull, and again, the next day... babies!! hehe

And its not like these babies were exceptionally large litters, or exceptionally large themselves. They didn't look more developed than regular pregnancy pinkies. Its almost like they go into stasis! hehe

Or maybe they just carried them differently, so they showed very early in the pregnancy?

W xx


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## SarahY (Nov 6, 2008)

I dunno what happened. Mice are right little weirdos, aren't they? :lol:

Sarah xxx


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## Onyx (May 2, 2010)

Swines, aren't they?! But congratulations =)

Quite a few people I know swear they have had mice hold on for 5 and even 6 weeks. The more I get to know other breeders, the more I hear about it, yet many still hold firm it isn't possible. It's not happened to me personally (yet lol) x


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## moustress (Sep 25, 2009)

At least you got babies. I have a doe, Lacey, who I was very excited about getting a litter from, but it came apparent after a few months that she was just getting fat...the first tri I've ever seen that did that. And I have a satin fawn doe who looked just plain fat until the day before she delivered, a common ocurance with some of my fawn lines. 'Weirdos' is a good word for it.


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## nuedaimice (May 26, 2010)

I have one like that now, she's seemed pregnant for several weeks, but hasn't given me any babies. Maybe I should go threaten to cull her?  I'll let you guys know if it works!


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## The secret garden (May 13, 2010)

Threatening is def the way to go it works, i've had a few do this to me too. Not by as long as 2 weeks tho a week for sure to the point i thought they would explode!!

If i ever get it happen i just clean them out and put there box on a different shelve next day babies, i know stress isn't good for them but sometimes it helps them a long a little.


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## tom95 (Apr 1, 2010)

Did you see how many babies did she breed ?


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## SarahY (Nov 6, 2008)

She had 14 - 12 bucks and only 2 does! And one of the does was too runty to keep :roll:

Oh well, hopefully I'll have some ivory bucks with good rosettes.

Sarah xxx


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## HemlockStud (Apr 26, 2009)

Sarah, what type of lighting do you use in your mouse room? The lighting greatly affects the genders of your litters.

Regular bulbs give litters that are 70% male and 30% female.
Florescent bulbs give litters that are 30% male and 70% female.
Natural sunlight gives litters that are 50/50.


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## nuedaimice (May 26, 2010)

RainyDayMice....

you're giving away all my secrets... sheesh!!! LOL :lol:

Sarah, its true. I've been testing it on my mice, and it very much works.


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## Autumn2005 (Apr 21, 2010)

You wouldn't think that something like light source would affect gender... Just goes to prove that mice are strange lit'le critters! How about my mice? They are kept under a incandecent light, next to a large window with natural light, and florescent lights on the other side of the incandescent bulbs... :lol: :lol: :lol:


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## SarahY (Nov 6, 2008)

> Regular bulbs give litters that are 70% male and 30% female.
> Florescent bulbs give litters that are 30% male and 70% female.
> Natural sunlight gives litters that are 50/50.


Ohmigod, that would explain everything!!! I've been really struggling with my doves; I've been getting on average two does per litter for the last 8 months or so!! I've had to put on my website that I can't sell any mice for a while as my numbers are really low.

They are in my front room with an incandescent lightbulb and I keep the blind down in the summer so that the room doesn't get direct sunlight. If my problem is solved by switching to a fluorescent lightbulb I'll be so d*mn happy!! 

Sarah xxx


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## WoodWitch (Oct 18, 2009)

Very interesting....
It's sounds like the ramblings of a madman, but I'm willing to believe in just about anything.

How can it be?
Something to do with Vitamin D production maybe?


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## Onyx (May 2, 2010)

I'd totally believe this given that when we bred fish, light and temperature greatly increased the amount of girls in the siblings. A temp difference of just .5 % higher would get your roughly 30% more girls, 1. % would give you 60% more girls. It is also known in chickens that if an inci is a little higher or lower, you'll get more girls or boys.


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## WoodWitch (Oct 18, 2009)

Absolutely fascinating!

I still need to know why though?
Inquisitive mind you see 

I'll bet someone round here knows the answer.....


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## WillowDragon (Jan 7, 2009)

Hmmm... interesting!!

Since my mice are in a shed, the only light they get is natural... and I have never noticed a marked difference between males and females in my litters, obviously its different in every litter, but on average I seem to get about the same amounts of boys and girls! hehe

W xx


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## WillowDragon (Jan 7, 2009)

This must mean that different types of light have an effect on the buck mice right? Effecting what sperm they produce?

W xx


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## ccoryjohnn (Jul 2, 2010)

Hmmm very interesting!! My mice have been in natural light pretty much the whole time I've had them though I use incandescent at night time for myself before bed. I should be having a litter within a week so I guess we'll see what happens!


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## The secret garden (May 13, 2010)

This works in reptiles, higher temps for girls in the incubator. 
Mine are in naturally light i get about 45% bucks 55% does. I am never over run with boys what so ever, and there is no such thing as being over run with girlys.


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## CatWoman (Jun 19, 2010)

:ff to the store for different light bulbs:: :lol:

Just out of curiosity, how much does the amount of light matter in the gender equation? I've been trying to keep my mice in a "natural" day/night cycle of light, but we're all nocturnal creatures in my house (including me) so we tend to have lights on at night more than the normal home would.


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## nuedaimice (May 26, 2010)

Here is a link to some information on it:
http://www.rawfoodexplained.com/air-sun ... light.html

(scroll down and you'll see the part where it talks about genders in mice)

When I bred previously I had mice that were kept in a room that had both natural lighting (from a huge bay window) and fluorescent white light. My litters were usually 50:50 in the summer (when they had more natural light) and had more girls in the winter months when we tried to simulate summer months with the artificial lighting.

After an almost 3 year absence from the fancy, I just got new mice less than a month ago. Not knowing much about the mice I purchased, one of my first litters was 12 babies, 9 males and 3 females. I called the breeder and asked what kind of lighting they used, she told me regular light bulbs. I talked to her about the lighting and she had said that she had wondered about this as all of her litters had been predominantly male for the last year (with the only light they get from incandescent bulbs). The other litter I produced was about 50:50, and I asked this breeder and she said she uses natural lighting.

Since I have had the mice they have been kept in a closet (a very large closet, more like a small office), with the only light they receive being from the fluorescent light in the closet (as there are no windows). My next few litters born (after being under the fluorescents for a week before conception) from the same litter yielded 6 babies at 4 females and 2 males, 10 babies at 6 females and 4 males, and then 2 more litters from another breeder (these born together) 21 babies at 16 females and 5 males.

Its the strangest thing I've ever seen. And I am still taking notes... but so far, I'm very pleased with the results!


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## CatWoman (Jun 19, 2010)

Thanks!

I must be doing an ok job of balancing the light and dark for them, because I have 12 female mice of breeding age right now and 10 confirmed litters on the way. :lol:


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## SarahY (Nov 6, 2008)

OK, I know this is a reeeeaaally old thread, but I just wanted to say that the fluorescent lighting bloody works!! This knowledge is worth it's weight in platinum, honestly.

When this was discussed back in July, I rushed out and bought a load of fluorescent lights for my stud. Ever since then, every single litter I've had has been doe heavy. Thank you to everyone who suggested changing the lighting because I was really struggling to breed enough does to carry on the lines successfully 

Sarah xxx


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## bethmccallister (Mar 5, 2010)

Thanks so much for bringing this up again Sarah, as I had not seen the information on different lighting before and this is amazing news to me.

I also wanted to add that I witnessed something similarly weird with pregnancy about a month ago. I had a buck and a doe together until the doe gave birth to her first litter. The day that the babies arrived I removed the buck because I felt the doe would need a big break before having another. I should have taken the buck out sooner but hadn't desided on my breeding plans for him yet. 3 weeks later I was relieved to see that the doe had not been impregnated a second time. 1 week after that I was busy seperating the litter and noticed the doe had a HUGE belly. 3 days later she had another litter. Is it possible for the sperm of the buck to live in the doe for an extended period of time and then still be fertile and viable? I know this buck is extremely fertile but dang....


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## WillowDragon (Jan 7, 2009)

That sounds to me like delayed implantation... its common in rats apparently. not sure about mice though.


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## Jack Garcia (Oct 9, 2009)

Did you just change the bulbs in your mouse room or did you place lights over the cages? I've thought about trying different bulbs but I don't know if it would help me since I do keep a lot of males to adulthood anyway (I go by the philosophy that if a mouse is a very good/excellent example, I keep it regardless of sex).

I've read in the literature somewhere (though I can't remember where) that pregnant mice can delay delivery up to a week if they have babies already (such as in back-to-back litters) or even if there are younger mice present. I think it was in Nature magazine, but I can't remember that for sure. I'm useless today.


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## CatWoman (Jun 19, 2010)

I'm using 24-watt daylight balanced 6500K compact fluorescent bulbs in the regular fixture for the room where I keep my mice and I've covered the only window in the room with black-out. I'm getting 85% does across my litters with that.

I thought this was an interesting read on skewing gender too -

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC153606/



> Striking variation in the sex ratio of pups born to mice according to whether maternal diet is high in fat or carbohydrate
> Cheryl S. Rosenfeld, Kristie M. Grimm, Kimberly A. Livingston, Angela M. Brokman, William E. Lamberson, and R. Michael Roberts*
> 
> ~snipped some junk~
> ...


I haven't done any dietary tinkering yet, because I feel like I need to do more research, but I probably will in the future.


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## Wight Isle Stud (May 19, 2010)

Right, gonna tell my mice they must only do it with the lights on. Seriously though, I have known very famous fanciers from the past loose famous strains of mice because of buck heavy. THis is serious knowledge to have,and is confirmed by seroius breeders on the forum by practical experience, therfore its a fact. Thank you to the original poster. When my shed goes up, the lighting will be designed to reflect this amazing fact.


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## moustress (Sep 25, 2009)

Wonderful and useful information from the CatWoman again! Luv ya!


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