Evaluation of two different boar semen freezing protocols and their effects on semen quality after thawing

The aim of this study was to evaluate the quality of boar sperm using two different freezing techniques. The protocols were proposed by Westendorf and Paquignon. In both methods the seminal plasma is removed. In the protocol Paquignon the seminal plasma is removed at environmental temperature and the Westendorf protocol suggests that the plasma withdrawal should be made at 15oC. The sperm suspension was performed using a cooling extender comprised of egg yolk and sugar (glucose Paquignon and lactose Westendorf). The freezing extender was added to the presence of glycerol for both methods and Orvus ES Paste on the methodology of Westendorf. The freezing curve comprised cooling from 5 to -5oC at 3oC per min and then from -5 to -140oC at 40oC per min. The sperm motility and vitality, viability, osmotic resistance, total morphological abnormalities, abnormal tail, head and acrosome, the presence of proximal cytoplasmic droplet and motility degradation rate were evaluated. The method proposed by Westendorf showed greater sperm viability (P < 0.05) and fewer changes in midpiece. There was no difference (P > 0.05) between the techniques for the other parameters. It was concluded that the method proposed by Westendorf could be indicated in future research for frozen boar semen.