Influence of extender, freezing rate, and thawing rate on post-thaw motility, viability and morphology of coyote (Canis latrans) spermatozoa

The objective of this study was to examine the post-thaw effects of three cryoprotective extenders (Tris–fructose–citric acid extender, Tris–glucose–citric acid extender, and lactose extender), three linear freezing rates (−1, −6, and −20 °C/min), and three thawing rates (37 °C water bath for 120 s, 60 °C water bath for 30 s, and 70 °C water bath for 8 s) on coyote spermatozoa. After thawing, the findings supported that cryopreservation of coyote (Canis latrans) spermatozoa frozen at a moderate freezing rate (−6 °C/min), in either a Tris–fructose or Tris–glucose extender, and thawed at a slow rate (37 °C water bath for 120 s) or moderate rate (60 °C water bath for 30 s), resulted in a more vigorous post-thaw motility (range, 57.5–44.0%) and viability (range, 64–49.6%) with the least amount of morphological and acrosomal abnormalities.