Assessment of the interaction between straw size and thawing rate and its impact on in vitro quality of post-thaw goat semen

Abstract

The objective of this study was to analyze interactions between different straw sizes and thawing rates on the post-thaw goat semen parameters. Twenty-one ejaculates (seven per animal) were collected from three stud bucks by using an artificial vagina. After evaluation, the semen was extended in Tris-egg yolk-glycerol and packed in 0.25 and 0.50 mL straws, followed by storage in liquid nitrogen. Thawing was performed using two different rates: 37 °C/1 min and 55 °C/7 s. The interaction between the 0.5-mL straw and the thawing rate of 55 °C/7 s promoted higher progressive motility. When the effect of straws alone was analyzed, it was verified that the use of the 0.50 mL straw promoted better conservation than the 0.25 mL one for progressive motility and acrosomal integrity, after the frozen-thawing procedures. Optimal results for progressive motility were achieved when goat semen was frozen in 0.5 mL straws and thawed in water at 55 °C/7 s. © 2012 Sociedade Brasileira de Zootecnia.