Comparative effect of different concentrations of hydro-ethanolic extract of chamomile on freeze-thawn semen quality of rams

Oxidative stress during freeze-thawing process causes reduction in motility, viability, membrane functions and finally sperm fertility. The aim of this study was to determine the effect of Chamomile extract as natural antioxidant on quality of cryopreserved ram sperm. In this study semen was collected from five mature rams twice a week using an artificial vagina and the ejaculates were pooled equally in order to eliminate the individual effects. Different levels of extract of Chamomile (0, 50, 66.66, 100 and 200 ml/dl of diluent solution) were added to diluent based tris-egg yolk. After cooling, filling and sealing of the samples, they were frozen with nitrogen vapor and immersed in liquid nitrogen and were stored until evaluation time. After thawing, results showed that addition of 66.66 ml/dl of extract increased total motility, progressive motility, curvilinear velocity, straight–line velocity, linearity, viability and plasma membrane integrity of sperm compared to the control and other treatment groups (