Variability of the effects of rearing in a large litter on the development of the rat.
The variability in the effects of rearing rats in large litters was examined. Subjects reared in litters of 16 were stunted and delayed in the appearance of eye-opening and fur-eruption as compared with pups reared in litters of 8. However, the effects of the large-litter treatment were not uniform; pups in this group exhibited markedly higher variability with regard to all measures than did pups from small litters. In fact, some pups from the large litters were heavier and some exhibited developmental landmarks earlier than did most pups reared in small litters.
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development*; D001835:Body Weight; D001942:Breast Feeding; D003163:Competitive Behavior; D005260:Female; D008098:Litter Size; D008297:Male; D009425:Nesting Behavior; D009748:Nutrition Disorders / Q000209:etiology; D011247:Pregnancy; D051381:Rats; D012107:Research Design; D012737:Sex Factors