Breeding Management of the Difficult Stallions in Artificial Insemination Programs

Approval of artificial insemination by most horse registries has resulted in commercial application of a multitude of assisted reproductive technologies to maximize the reproductive efficiency of with reduced fertility. Strategies that are becoming more commonplace in equine breeding programs include cushioned centrifugation of semen, density-gradient centrifugation of semen, and deep-horn low-dose insemination. These techniques are being applied to semen from stallions in situations such as low sperm concentration, poor semen quality, and low total sperm output.

Cushioned centrifugation of semen - Centrifugation of semen is oftentimes applied in equine breeding programs for increasing sperm concentration and/or for reducing seminalplasma concentration in extended semen. As such, the value of improving centrifugation procedures to maximize sperm harvest, without associated sperm injury, becomes apparent. Development of a more efficient centrifugation method, i.e., one that increases postcentrifugation recovery rate while maintaining semen quality would optimize the number of sperm in an ejaculate that are available for breeding purposes. One of the main concerns, when attempting to maximize sperm recovery through centrifugation, is the adverse effect that centrifugation can have on the integrity of sperm. Typically, an increase in centrifugation time or gravitational (g) force results in an increased sperm recovery rate, but it can also lead to decreased sperm motility or quality due to the mechanical forces associated with centrifugation and excessive packing of the sperm. Ideally, centrifugation should result in a 100% sperm recovery rate with no resulting damage in sperm quality. These goals are not attainable with traditional centrifugation techniques […]