In conclusion, the 0.8% lecithin extender containing catalase, conserved P and V during 8 d of cold storage better than the TRIS-EY extender, however, only when an enhancer was used addition of acetylcarnitine to the enhancer did not further improve semen quality. The ZBA showed that with additives, significantly more spermatozoa bound to oocytes when a lecithin extender with additives was used (P < 0.05). The chromatin status of cells was not changed by cooling within 8 d. The percentage of capacitated spermatozoa did not differ between extender groups and there was no significant increase in acrosome reactions (AR) within 3 d. The use of an enhancer proved to be essential for all extenders and after 8 d of cooling, progressive motility (P) and viability (V) still averaged > 70% and > 80% with the lecithin extenders containing additives, whereas with TRIS-EY and without additives it was significantly lower (P < 0.05). Measurement in the CASA were repeated daily and prior to measurement, each sample was diluted with each of 4 enhancers with or without acetylcarnitine. Samples were then cold stored for 8 d and examinations repeated at days 3 and 8.
All samples were examined by computer assisted sperm analysis (CASA), chlortetracycline assay (CTC) and flow cytometry, sperm chromatin structure assay (SCSA) and zona pellucida binding assay (ZBA). For this purpose, aliquots of 10 mixed ejaculates (main fractions) were either diluted with TRIS-EY or with three lecithin extenders containing 0.8% lecithin with or without catalase and tyrosine. Hereby the semen is deposited directly in the uterus by means of an endoscopically guided flexible catheter.In the present study, a diluent containing 0.8% lecithin (Minitube®, Tiefenbach, G) for the cold storage of canine semen was compared to a Tris-egg yolk extender (TRIS-EY) containing 20% egg yolk. In general the results of inseminations with chilled semen can be just as good as a natural mating if the semen after collection is of good quality, the timing is good and the insemination is done by TCI. This is the minimal amount of semen needed for fertilisation (100-150 million sperms with good motility and morphology).įor optimal results the best way to organise matings with chilled semen is to ensure that there is a maximum timeframe between the collection and the insemination of 36 hours. The price of freezing is higher than chilling and the transportation of frozen semen is more costly because of the need of using special containers with liquid nitrogen (dry shippers).Īnother advantage of using chilled semen is the use of the total collection for shipping and insemination while with frozen semen a collection is most of the time divided into several breeding-units. The costs of using chilled semen in total (collection, extending, packaging, transportation) are less than using frozen semen. You can see a photo of the box shown here.Īfter arriving at the destination the semen can be stored in a refrigerator if more time is needed for the female to reach the optimum time period. For most destinations this is enough to send the semen without loss of quality. The USA and Canada are countries where we can send chilled canine semen to with good results.įor the actual transportation at 4 degrees centrigrade we use a disposable box that can hold the cooled semen for 2 days. In that way an objective documentation is warranted.Ĭhilled semen is very easy to use in case of a short period of stocking the semen or for distribution within Europe and to other countries where quarantine regulations make it impossible to do so. It is also possible to email the moving images and the morphology images. We can send this digitally to the owner of the male and the receiving party before sending the semen. Right after the collection we complete a quality assessment before and after extending.
The extenders are: Canirep, Mofa and Minitube. We use different extenders depending on the time needed to cover and the specific semen factors. The capability of fertilising ova is most of the time much less possible. Depending on the quality of the semen, the extender and the cooling curve it is possible to keep the motility up to 10 days. The preservation of semen for several days is possible by spinning it immediately after collection and adding a chilled semen extender and gradually cooling it to 4 degrees centrigrade.
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