The current study was conducted to euraiuate the effects of dietary supplementation of YC (Gustor nature} With or without premrx on reproductive performance of buffalo cows during summer ano Winter seasons A total of 42 iactatmg Egyptian buffalo COWS weighng 500-650 Kg. aged 3-9 years and between 1.5 parites were used in the study for two seasons, winter and summer. Within each season. the experimental animais were dimded in:o three :éetery groups Group 1. fed basal diets Without supplementation and kept as control group Group < /p> 2, fed basal diets and supplemented wit‘r 20 g yeast culture (Custer naturefi'h.‘d Group 3, fed basal diets and supplemented With 20 g Gustor nature and 35 g premm‘ht‘d Total animals in each group were seven buffaloes All animals were fed the tested diets one-month prepartum and 6 months postpartum The obtained results indicated that postpartum 1st ovulation interval was longer (P