The effect of spirotetramat, extract of Tribulus terrestris (TT100, TT50) on body weight (g) and testicular volume (mm3) of male pigeons (Columba livia domestica) (n=5) during 10 weeks of treatment under a long photoperiod (19L:5D). SPT: Spirotetramat (15mg/kg.BW/day), TT100: Tribulus terrestris (100mg/kg.BW/day), TT50: Tribulus terrestris (50mg/kg.BW/day). Values= Mean ± SD. Methanolic extract of TT caused a significant increase in the bodyweight of pigeons. SPT induced a decrease in testicular volume. However, methanolic extract of TT could improve the testicular volume significantly.