This article is from the WSSF 2016 AFRMA Rat & Mouse Tales news-magazine.

By Karen Robbins

Jennifer Kelly, Rough & Puff Rattery, TX
Q What causes female rats to have litters with only a couple really big dead babies being born?

A I wasn’t able to find anything specifically about this question, but Ann Story wrote about small litters and big babies in the Common Diseases of the Fancy Rat book. From page 35 in the book: small litters may be due to the male having low sperm count, poor quality of sperm, or inability to stimulate the does ovaries to produce eggs; pp. 37–38 Delivery Problems: Does from inbred lines when outcrossed sometimes carry large numbers of big foetuses which stretch the muscles of the abdomen to the point where it is difficult for them to function properly. These does are especially likely to have a slow labour and to produce a dead litter. and ...problems have occurred with big single kittens (giant kitten syndrome)... p. 39: Giant Kitten Syndrome has been reported in black eyed whites, capped rats and some others. The doe gives birth to kittens one of which will be at least twice the normal size. The legs are usually the same size as in a normal kitten however and the kitten is born dead. The cause is unknown but it is thought to be inherited.

And in Pro-Rat-A (PRA; National Fancy Rat Society [N.F.R.S.] newsletter) #157 Jan./Feb. 2007, there was a question about caesareans. A doe had gone to day 26 in her pregnancy with no babies, they did a c-section and found 3 over large kittens, two were dead and one survived about half an hour. The answer from Veronica Simmons told about c-sections being rare and usually not necessary, problems having the kittens may be due to the first kitten being too big.

In PRA #86 March/April 1995 the question was about stillborn litters, a rat went to day 25 and passed seven stillborn kittens, Ann Storey wrote the reason could be hormonal or an infection. Hormonal problems including female infertility, uterine inertia and abortion are all commoner in the cold season.

You can also read these pages:

• Advice for the Novice Breeder
• Rat Breeding Part 1: Biology
• Fertility Problems and Litter Loss

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