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 −0.3°C/min and a final temperature of 4° to 5°C (Douglas-Hamilton 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 made by manufacturers of some shipping containers, have led to concern regarding the ability of disposable containers to maintain satisfactory cooling rates and/or storage temperatures during transportation (Blanchard et al., 2003), which may, in part, be due to information published by companies responsible for air transport of semen in an effort to prevent liability caused by damage during shipment of temperature-sensitive items such as feedstuffs and other biological materials (Casada et al., 2003). This information might lead to the conclusion that the containers would normally be subjected to temperatures ranging from −70° to 145°F. These results suggest that some of the disposable static cooling devices on the market may not be suitable for shipping semen, despite successful research and field use (Katila et al., 1997; Dawson et al., 1999; Webb and Arns, 2004).