The performance of Hippex.
The performance of Hippex is illustrated by a comparative analysis of 5 commercial extenders, including Hippex, using computer-assisted sperm analysis (CASA system CEROS II from Hamilton Thorne).
The quality of semen diluted in Hippex and in four other commercial extenders was determined during storage of the diluted semen in the respective media.
The results are shown in the graphical presentations below.
Image showing a graphical presentation of the percentage of sperm cells that are motile (total motility) during storage of the sperm cells in the different extenders.
Image showing a graphical presentation of the percentage of sperm cells that are progressively motile during storage, which means the percentage of cells with a relatively high velocity ( > 75 micrometer/sec and a rather straight line of movement namely a straightness ratio > 75).
Hippex shows here for both total motility and progressive motility the best results of the diluents investigated using the ‘’non-centrifugation method’’. These results have been confirmed by analysis of different ejaculates from different stallions at different dilution rates. The preserving capacity depends also on the stallion, but in all cases, Hippex was better or at least equal to the next best one, which was either INRA96 or Spervital, depending on the stallion.
The possibility to determine the fertilizing potential of stallion semen before use in artificial insemination is very important for maximum reproductive efficiency of stallions as well as for management of ejaculate processing, a.o. the dilution rate.
Several studies showed very high correlations among sperm motility characteristics (in particular progressive motility) and stallion fertility. To monitor the fertilizing potential during storage of the sperm cells, motility characters (determined using CASA) can serve as a tool to assess the quality of the diluent used.
(see: Relationships among stallion fertility and semen traits using estimated breeding values of German Warmblood stallions
Gottschalk, Maren et al. Theriogenology , Volume 89 , 68 - 71)
While these correlations indicate that the use of Hippex maximizes the fertilizing potential of stallion semen, the ultimate proof comes from monitoring pregnancy rates.
Hippex and Pregnancy Rate.
The results of the large-scale use of Hippex (with and without centrifugation) during the past 2 years (2017 and 2018) showed a pregnancy rate of 75 - 80 %.
These results confirm the high correlation between motility characteristics and fertilising potential. The use of Hippex resulted in an increase of 10 - 15% pregnancy rate when compared to the use of other commercial extenders such as Spervital, Botusemen and INRA96.