الفهرس 
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Abstract
The obtained results showed :-A. Reproductive behaviour :
1-The female Rattus rattus attained puberty at 61 day as revealed by ovaries weight and histological picture.
2-The vaginal smear and behavioural observations revealed that the proestrus extends from 15 to 18 hour, estrus extends to 13 hour , metestrus exends from 16 to 18 hour and diestrus 76 to 90 hour . The total time of the cycle ranged from 5 to 6 day .
3-The ovaries were found to be 73 mgm at 30 day of age and 330 mgm at one year . The increase in ovary weight was not directly proportional with age . The most active ovary was at 325 day as revealed by its weight and number of follicles .
4-The uterus began for reception of the first preg-nancy at age of 7C to 80 day of age as revealed by increased cell proliferation and cell size of endometrium as shown in morphological features . 5-The weight of the foetus increased by age , but the increased number was accompanied by decreased individ-ual weight .
6-The litter size during the work ranged between 1 to 10 young (mean 6) and the pregnancies ranged between 5 to 8 birth per year with an average of 50 young per female per year .
7-Weaning naturally occured at 25 day of age . Artificially weaning at 20 day had no effect on growth rate .
8-Life span in captivity reached 28 month and females lived longer than males .
Growth :-
1-Growth rate of Rattus rattus was not affected by the number of the litter pre- or postweaning .
2-Growth rate was markedly increased at 1 3 , , 12 and 15 weeks of age .
3-The weekly gain in body weight averaged 5.1 gm from one week to twelve weeks of age . The selfaccel- erating phase of growth was from 12 week to 16 week of age .
4-After 18 week of age , the relative growth of young was nearly constant .