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Abstract
In Experiment 1, cooling rates and final storage temperatures of two commercial static cooling devices were compared during air transit utilizing internal temperature loggers. The cooling devices were shipped from Tucson, AZ to Springfield, MO and consisted of a reusable device (Equitainer I®; Hamilton Research Inc., Beverly, MA) and a disposable device (Equine Express®; Exodus Breeders Supply, York, PA). Cooling rates were compared during summer and winter shipments, as was the percentage of progressively motile sperm following transit. In Experiment 2, cooling rates were determined in four static cooling devices held for 48 h at a controlled-environmental temperature of 22°C. During actual transit, the mean and minimum internal temperatures reached were less (P<0.0001) when shipping occurred during winter. However, internal temperatures were not different within season between containers. Neither season nor container affected the percentage of progressively motile spermatozoa 24 h post-packaging. When ambient temperatures were controlled at 22°C, cooling rates from 19° to 10°C were similar between the Equitainer I® utilizing centrifugation tubes (-0.033 ± 0.002°C/min) and the Equine Express® (-0.035 ± 0.005°C/min); both of which provided slower (P<0.001) cooling than did the Clipper (-0.098 ± 0.005°C/min) and the Equitainer I® utilizing a cup-style isothermalizer (-0.077 ± 0.01°C/ min). These data suggest that, during both the winter and summer months in the southwestern US, disposable cooling devices can be used to ship or store stallion spermatozoa for 24 h.
(Key Words: Stallion, Shipped Semen, Cooling Devices.)
Introduction
There has been a great deal of activity in the use of transported stallion semen, as most of the major breed registries in North America approved its use in the late 1990s. Producers have access to several commercially available cooling devices for use during the transportation of stallion semen. Initial studies were conducted with a reusable, rigid container (Equitainer®; Hamilton Research, Inc., Beverly, MA) that was reported to provide a cooling rate of 0 -0.3°C/min and a final temperature of 4° to 5°C (DouglasHamilton et al., 1984). Brinkso et al. (2000) compared cooling rates and lowest temperatures reached when several reusable and disposable cooling devices were subjected to different ambient temperatures and suggested that the improved version of the original rigid device outperformed some of the disposable devices. Interpretation of these results, along with claims...