Abstract: This study aimed to evaluate postpartum associated metabolism as an adaptive indicator for lactational stress, milk production and reproductive efficiency of two subtropical sheep breeds. Blood samples were collected from Rahmani (n = 15) and Barki (n = 15) ewes, 14 days postpartum and at biweekly interval thereafter (until day 56 postpartum). Milk yield and milk composition were determined and were used to calculate energy corrected milk, milk energy value and energy required for lactation. Ovarian activity was biweekly monitored using transrectal ultrasonography until day 56 postpartum and then ewes were synchronized for estrus 60 days postpartum and were mated. Rahmani ewes had greater (p<0.05) overall concentrations of serum glucose, total protein and insulin than Barki ewes. No differences were observed between the two breeds in the concentrations of serum urea and T3 hormone. Milk yield of Barki ewes was higher (p<0.05) than Rahmani ewes, but energy corrected milk was in the same trend. Further, Rahmani ewes tended (p = 0.09) to produce milk with higher energy value. The calculated net energy required for lactation was in the same average in both breeds. No differences in milk composition were observed in both breeds, although, percentage of total solids was higher (p = 0.07) in Rahmani ewes. Following estrous synchronization, Rahmani ewes had higher (p<0.05) number of corpora lutea 11 days post-mating and lower embryonic loss (p = 0.14), also they had higher conception (p = 0.09) and fecundity (p<0.02) rates compared with Barki ewes. In conclusion, postpartum metabolic profile could be used as an indicator on breed superiority to subsequent productive and reproductive performance.