Chilled semen is a technique used in equine breeding to transport and preserve stallion semen for artificial insemination (AI) without requiring the immediate use of fresh semen. This method allows breeders to extend the viability of the semen, making it possible to ship it over longer distances and use it at a later time. Here's how the process works: 1) Semen Collection: The stallion's semen is collected using artificial methods such as an artificial vagina or a collection cone. It's then evaluated for quality and concentration. 2) Semen Dilution and Extending: The collected semen is diluted with a special extender solution that helps protect and nourish the sperm while also providing a medium for transportation. The extender helps to slow down the metabolic processes of the sperm and maintain their viability. 3) Cooling: Once diluted, the semen is gradually cooled down to a specific temperature (usually around 4-5 degrees Celsius). This cooling process slows down the sperm's metabolism, further extending its viability. 4) Packaging: The chilled semen is then packaged in special containers designed to maintain the cooled temperature during transport. These containers are often insulated and may include cooling packs or other temperature-regulating mechanisms. 5) Transportation: The packaged chilled semen is transported to the mare's location. The goal is to minimize temperature fluctuations during transportation, as temperature changes can impact the viability of the sperm. 6) Insemination: Once the chilled semen reaches the destination, it can be used for artificial insemination of the mare. The semen is carefully deposited into the mare's reproductive tract, typically using a veterinary-assisted procedure. It's important to note that while chilled semen can significantly extend the reach of stallion genetics and increase breeding options, there is still a limit to how long the semen can remain viable. Chilled semen has a shorter lifespan compared to frozen semen, which can be stored for much longer periods but requires more complex procedures for both collection and storage. Overall, chilled semen technology has been an important advancement in equine breeding, allowing breeders to access genetic material from stallions located far away and contributing to the preservation and propagation of valuable bloodlines.