Rat Infant Mortality Rate

[hhw]

Yesterday, one of my female rats had a litter of 11. Upon inspection, 3 of them were dead. Now, since I'm under the impression that female rats will chew off the umbilical cords of the young and if the babies don't squeak and squeal when that happens (which a live one would), the female will just keep on and eat the dead baby. Since those 3 were intact without umbilical cords or any placental mess, I assume that they were born alive and died sometime after. Today, I found a 4th baby dead.

Now, initially I had the pair in together (female and the male), but I removed the male when I discovered the babies. I assumed that that may have been the reason the first 3 died (by pestering the female or whatnot), but that would not explain the fourth.

So, my question is is it natural for some of the babies to die off like this the first day or two due to not being able to compete for milk, or am I doing something wrong husbandry wise here?

[mice4you]

I would not jump to conclusions until you see another litter. New mothers sometimes don't do a great job the first time around. They are nurvous and can also have milk supply issues. If it happens on the second litter, I would replace the female.

I have found this problem to be more prominant in mice however I have seen it numerous times with rats from our buildings. The first time we let it go but if it continues, they become retired breeders quickly.

[Linds]

In addition to what mice4you said, there isn't really any reason that the father should've caused the deaths in this situation. Most 'murders' of healthy rats are done by the mother, or other females I find. The fathers typically do a good job of being a father to their young. I never seperate my males, as I find it highly counterproductive.

[mykee]

I'm with Linds, keep the colonies intact throughout the births; tighter bonds.

[mice4you]

I agree with Linds. The only thing that normally happens when removing the male is that you have to wait longer between births.