The present study aimed to assess the impact of season, sex, 
year, parity, and birth type on the growth performance of Sohagi 
sheep. Data were collected from 1391 lambs born between 2001 
and 2021 at the experimental sheep farm of the Animal 
Production Department, Faculty of Agriculture, Sohag 
University, Sohag, Egypt. The influence of non-genetic factors 
on lambs' average daily gain from birth until one year of age was 
calculated. Results show that average daily gain until 3 months 
(ADG1) and average daily gain until 12 months (ADG3) were 
significantly affected by sex (P<0.01), while average daily gain 
until 6 months (ADG2) wasn't affected significantly. Also, 
ADG1 and ADG3 were greater in males than females, while 
ADG2 in males was close to that for females. The ADG1 and 
ADG2 were significantly affected by birth type (P<0.01), single 
and twin lambs were grown faster than triplets. The ADG2 of 
lambs born to ewes of 3rd, 2nd and 4th parities was higher than 
those of 1st and ≥ 5th parities, but it wasn't significantly affected 
in each ADG1 and ADG3. Thus, it can be concluded that nongenetic factors affected the average daily gain of Sohagi lambs 
during the first six months after lambing and up to one year of 
age. Therefore, it must be taken into consideration when 
designing selection programs to improve the performance of 
Sohagi sheep.