The influence of litter size and favourable conditions on mortality and weaning weights in rats.

Litters of 12 pups produced the optimum results for survival (P less than 0.005) and for weaning weights (P less than 0.05) when compared with litters of 8 and 10 pups. This number is similar to the normal litter size and normal number of teats in rats. In our study, the normal litter size was means = 12.5. Our results were obtained under favourable conditions without disturbing the animals and facilitating access to food and water for the mothers and pups.