Mice off spring

Question
If I had 1male&1female mouse how many mice might I have in 1 year

Answer
Hi Franklin,

There is a lot more to breeding than that, but the short answer is about 20-30 pups.  Here's how I got that number:

Let's assume you have three successful litters.  That's really the most a lot of people will recommend you mate one female, as pregnancy is fairly taxing on a mouse and overbreeding her can result in complications and lost mice.  At an average, you'll probably have 6-10 pups per litter - at a guess around 20-30 offspring.  There's no guarantee at all, however.  Some moms will eat their first litters, and most have smaller first litters.  I'd recommend against breeding a mouse who is over a year old - it's possible, but older mice have higher chances of complications, lower fertility rates, and smaller litters.  On the other end of a spectrum, I'd wait until a female is about 3 months old before breeding her to ensure her body is mature enough to handle pregnancy, or you may wind up with no pups and a lost breeder doe.  This gives you a 9 month window for the female, and if you give a female space between pregnancies (back-to-back pregnancies are extremely risky, so always separate the male before she has her pups), you come up with about three good, healthy, low-risk births.

Please read up on breeding mice long before you pair them, if you intend to do so, and always follow good quarantining procedures before mating.  It's tough to treat a sick female while she is nursing and can result in a lot of lost mice and money - give them a good three weeks of isolation before pairing a male and a female so you can watch for illnesses to develop or poor traits, behaviors, or body types that you don't want passed on.  Here are some good sites for learning about mouse breeding:

http://www.hiiret.fi/eng/breeding/index.html
http://fancymice.info/breedfrontpage.htm

-Tam