Abstract
Simple dilution of semen is the oldest method to process semen for
artificial insemination with either fresh or cooled. This was developed
prior to the optimization centrifugation techniques for semen through a
combination of trial and error and research. Simple dilution and is a
faster method to process semen, is easy to use and works in many
circumstances. For on farm semen use a 1:1 (v/v) semen to extender ratio
is used. A variety of other techniques have been developed, such as
cushion centrifugation, density gradient centrifugation and sperm
filtration. Cushion centrifugation is used to concentrate the sperm and
allows higher centrifugation speeds than centrifugation alone. This
allows for improved recovery rates of sperm. Density gradient
centrifugation has been used to select for morphologically normal sperm
but suffers from low recovery rates. Processing sperm with this
technique can result in improved motility and improved DNA integrity of
sperm. Sperm filtration is another method to concentrate sperm without
the use of centrifugation; however, this technique has lower recovery
rates compared to cushion centrifugation. This review will discuss these
techniques in the application of processing equine semen for either
fresh or cooled-shipped use.