Timed pregnancies in mice - Do you have any tips or tricks? (Jul/12/2006 )

We've been trying to set up some timed pregnancies and I was wondering if anyone has any secret tips or tricks that they could share. We've just simply been putting them together and this has given us limited success. So, right now we are trying to put the female in the male's bedding 2 days before we actually put them together to encourage her to initiate the estrous cycle. Someone had recommended reintroducing the male on the third day after their first introduction (and removing the following morning) then looking for a change of weight of the female 9-10 days (if the first mating was successful) or 11-12 days (if the second mating was successful) after they were first introduced. There was also some talk of vanilla beans (??)

Any ideas or input?

Thank you!

My PI says that ordering timed pregnancies from companies like Charles River or others are much better. One gets more pups and they r quite reliable and not very expensive.

We are working with some transgenics we made, so we can't order the timed pregnancies (although that sounds like it would be the way to go).

try getting some help from the animal care takers. they r usually trained for such things.

Goodl Luck !!!

I think our animal facility adds a supplement to the diets of ones that are difficult to breed. You might see if your facility knows anything about something like that.

Instead of checking weights, why not check plugs? The morning after mating (be sure it is earlier-8am or before-or you might miss it), check to see if the male has left a "deposit" in the female. It is pretty obvious to the naked eye, or you can take a spatula and gently see if any matter can be moved. This does not help them breed, obviously, but it allows you to know if and when mating has occurred.

As far as encouraging them to breed, the different feed is a good idea and a couple other breeding clues (though some might be "old-wives tales:"

1. Always put the female into the male's cage
2. Sometimes breeding one-on-one (not breeder trios) is more successful. After mating, you can always put females in the same cage as one another.

Also, make sure your animals are younger, as older animals sometimes breed worse. Definitely check with your caretakers on any helpful hints. Hope it helps. I think we are in the same boat-I too am a slave to a mouse's reproductive capacity and I hate it!

Thanks for all the input!

We've had better success this week - plugs and embryos! Not with every female, but about half. I think putting her in the male bedding has helped, which is what our animal tech recommended.

In the past, we've seen plugs and no embryos and on a couple of occasions missed the plug and ended up with babies

At least I'm not alone
Thank you!

of course you are not alone! i also use plug checking method and the successful rate is about 2/3

and just for information

putting female into male cage is better because the male has already established its "territory" in that cage! if you do the reverse, the male is not likely to mate quickly because it needs time to adapt to the new environment. this's what my caretaker told me about setting mating