# Heat affecting breeding?



## Autumn2005 (Apr 21, 2010)

I've been breeding for almost 3 years now. I started October 2009, so I'm just a couple months shy of my 3 year anniversary. One thing I've noticed, is that my fertility rates tend to go way down during the summer. The first two years (summer 2010 & 2011) the mice were inside the house. We use the AC, but the temp in the house still regularly gets over 80*F. (It's worth noting I live in southern CA, where outside daytime temps during the summer often get above 100*F and stay there for days or weeks at a time.)

This year, summer 2012, the mice have been in an outside insulated shed since about February. That worked well until the really hot temps started to hit about a month ago. After losing nearly half my mousery (including the best typed buck ever born in my mousery, thankfully he accidentally nailed his mothers and sisters before I removed him, so I still have some of his offspring), I put my foot down and brought the mice back inside. (Have a carpenter coming tomorrow to install AC in my shed.)

One thing I've noticed, is that during the cooler months, I usually put 2-3 does in with bucks every 10 days (I have snakes that eat everything from pinkies to adults, so I cull a lot to avoid overcrowding), and I can count on all of them getting pregnant within the first couple days, 90% of the time. During the summer, I will sometimes put as many as 9 does to various bucks on my breeding days, and I am lucky if even 2 of them get pregnant. I generally leave the does with the bucks for at least 10 days, and usually much longer, until they're visibly pregnant.

tl,dr Summery:

Has anyone else experienced reduced fertility during the warmer months?


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## Shadowrunner (Sep 26, 2011)

Absolutely. Especially this year with the temperatures reaching almost 113 outside.
The humidity doesn't' help either.

I give them cold water, I move them to the basement, but even then it hovers around 80.

Even when they do conceive, a lot of the litters are born premature or the mothers can't seem to handle it.


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## Autumn2005 (Apr 21, 2010)

So I'm not imagining it! That's a relief to know, now how to fix it? I'm getting an AC installed in my shed tomorrow, and I'll see what temperature I can keep it at and still afford the bill... Since the shed is insulated, and 96ish square feet, and the AC can cover upto 250 square feet, I'm hoping the AC will need little power to keep the shed at a reasonable temperature.

Interestingly, of the 9 does I bred 3 weeks ago, only one conceived, and gave birth today to 12 babies, 4b and 8g. I might keep her in the cooler house until her babies are quite developed.

So how do you cope with the heat affecting your fertility? Do you cull less, breed more, or just sit and the shade and wait for the heat to pass? (Good luck on that... CA has 2 seasons: 3 months of almost cold, and 9 months of heat, with at least 3 months of hell-high temps during the hot season...)

Maybe in the future I'll plan not to breed during the hottest part of summer?


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## We Love Mouse (Jan 5, 2011)

I've heard from other feeder breeder here too that their mice won't breed in hotter months [like April-May]. I think it could be that the males are getting tired easier / more interested in cooling themselves than breeding or the heat reduce sperm production.


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## PPVallhunds (Jul 26, 2010)

The heat was out of their control and they took measures to prevent it happening again, that is why no has 'had a go' as they didnt nothing wrong. Ive not noiced anyone having a go at you mousey_girl (but ive not read all the posts on hear), not everyone agrees and people are allowed to dissagree and to say why they feel like that. The only one i saw where people did that to you was on your shrew thread.

Back on topic Ive hurd a few people have lost some mice to the warm weather reasontly, luckerly allthought my shed has been getting warm everyone here is ok. Ive been leaving a window open to leat the heat out and as the window is facing the house it doesnt seem to let a draft in.


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## Autumn2005 (Apr 21, 2010)

Did I miss something.....?

Anyway, yeah I got my AC in the shed, put the goo that inflates around it to seal the cracks and stuff (still trying to get it off my fingernails... had to cut a section of my hair off too) and it still gets warm in there, but over all is much nicer.

And I did the typical girl thing and decorated.... I now have curtains!!!! It also helps keep the heat down too without hot sunlight coming through the windows. The only thing is, it's much darker in there, which means I'm using lights more.

So I have another question now: does the amount of light affect breeding? I know the sexes can be affected by the /type/ of light used, but what about the /amount/ of light?

For example, horses grow and lose their winter coats according to how much light there is. That's why my horse is now growing her winter coat, even though it's still blazing hot, because the equinox has passed and the days are getting shorter. Show horses will often be taken into a barn and kept under artificial lights, to either delay the growth of winter coat, or to encourage them to shed it faster.

Is it possible having less light (the light's only on when I'm in there) can make the mice breed less/more? I'm considering a timer for my light....


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## PPVallhunds (Jul 26, 2010)

yeah mousey girl posted above me and i was replying to them, but there post is gone so i guess a mod removed it. Trust me you didnt miss much.

As for the light thing, mine dont get much light being in my shed with 1 small window facing the house and not had any problems yet, the oens at work do have a uv light bulb in the room. Im pritty sure i read somewhere that shorter days could make them breed more as they are more active when it gets dark. but i cant realy rember if i did actualy read it or not, so could be wrong.


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## moustress (Sep 25, 2009)

Mylar, also known as space blanket or emergency blanket is a very superior material for covering windows and uninsulated walls. It deflects heat or cold from either side, is pretty cheap. I try to find the lightly heavier gauge blankets which keep the metallic coating and last much longer. We use them during hot and cold spells to cut down heating and cooling bills. they cost anywhere from $2.to $6.

We also keep a couple of them in the car for cold weather or other emergencies. I buy them three or six at a time, when they are on sale;they were developed by Nasa to deflect the sun from sensitive equipment in space. I love them.


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## Autumn2005 (Apr 21, 2010)

Yet another great suggestion from moustress.... I'll have to keep my eyes open for the mylar. Do you put it on the room, or tack it to the ceiling, or hang it from the windows, or what?


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## sugarmice (Jul 24, 2012)

Interesting thread, did not realise that heat could affect breeding.


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## tinyhartmouseries (Dec 30, 2010)

Oh absolutely. I had a bit of a lull this summer until we put the mousey's AC in. Then, two females caught the next day. Very very common problem!


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## Autumn2005 (Apr 21, 2010)

What temperature do you keep the ac at? I tried to find a temp that kept things cool, yet didn't run the electric bill up way too high. I swear, it's almost worth getting sun panels, you know?


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## tinyhartmouseries (Dec 30, 2010)

I think it stayed at around 75 most of the time. Between the settings and the sunshine coming in, that is. I really need a thermometer for the wall...:S


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