Effect of soybean based extenders on sperm parameters of Holstein Friesian bull during liquid storage at 4ºC

Animal origin egg yolk extender has been associated with microbial contamination and interference with microscopic examination. Therefore, replacement of such extender with plant origin compound is inevitable without compromising the desired qualities of an ideal extender. In the current experiment, we compared the effect of soy-based extender (25% and 50%) of five adult Holstein-Friesian bulls semen preserved at 4ºC for 24 h with conventional egg yolk (control) and synthetic extender. Semen quality was assessed by measuring liveability, individual motility and membrane integrity after 24 h of extended semen stored at 4ºC. The results indicated that liveability, motility of sperm and membrane integrity decreased significantly (P<0.05) in soy 50% extender. The results of sperm liveability, individual motility and membrane integrity in 25% soy extender were comparable with the control. Therefore, we concluded that 25% soy milk could be used as a substitute of conventional egg yolk-based extender for bull semen stored at 4ºC.