Frozen semen
When frozen semen is sperm , which was preserved by cryopreservation. It is mainly used in artificial insemination for cattle, horses and some zoo animals, but also for artificial insemination in humans. Frozen semen can be stored practically indefinitely.
Production of frozen semen
After sexual stimulation, the seminal fluid is stored in a water bath warmed to body temperature immediately after the ejaculation. The volume and quality of the ejaculate are then determined. Important criteria for quality assessment are the sperm concentration (bull: 0.8 to 2.5 billion sperm per ml) and the percentage of motile sperm (bull: 60 to 80%). Before freezing, the seminal fluid is diluted. The thinner contains nutrients and protective substances such as egg yolk and sugar, buffer solution , antibiotics to prevent the growth of germs and glycerine as antifreeze. The addition of these substances serves to maintain the viability and fertility of the sperm. After filling the individual portions into special plastic tubes, so-called sequins (beef: content 0.25 to 0.5 ml depending on the system), these are cooled to +4 ° C for several hours in a refrigerator. The subsequent freezing usually takes place in special deep freezing machines or in the nitrogen vapor of a special container. Frozen semen is then stored in liquid nitrogen at −196 ° C. If this temperature is kept constant, the frozen semen can be kept almost indefinitely, while a slight increase in temperature can make it unusable.
meaning
Frozen semen is of particular importance in cattle breeding , where for example the bull Hanoverhill Starbuck had over 200,000 daughters and Toystory sold over two million servings. Starbuck's dam's sire, Osborndale Ivanhoe , was one of the first bulls used worldwide. With the hereditary disease BLAD , which he widespread , the problems of the blood supply being too narrow due to the widespread use of fewer bulls became clear. Frozen semen is also used in zoo animals and rare breeds of sheep. Frozen semen is hardly used in pig breeding. The large amount of ejaculate from pigs does not allow rapid cooling, which is why they work almost exclusively with fresh sperm.
Due to the stress during the freezing and thawing process, the fertilization capacity of the frozen sperm is about 15 to 20% lower than that of fresh sperm. The import and trade in frozen semen from animals are subject to legal regulations.
Frozen semen is stored in sperm banks for artificial insemination of women .
Artificial insemination using frozen semen is also becoming increasingly important when it comes to preserving endangered animal species. In July 2009, Chinese scientists succeeded in giving birth to two pandas for the first time in this way .
literature
- E. Grunert, K.-H. Lotthammer, M. Rüsse, J. Gaus a. a .: fertility in the cowshed. , ISBN 3-7843-2537-8
- A.-R. Günzel-Appel: Fertility control and semen transfer in dogs. Gustav Fischer Verlag, Jena 1994; ISBN 3-334-60512-4
- Top agrar, the magazine for modern agriculture (Ed .: Berthold Achler) (Hrsg.): Cattle insemination with success: Handbook for own stock inseminators. Landwirtschaftsverlag, Münster 2002, ISBN 3-7843-3127-0 .
Individual evidence
- ^ A. Riesenbeck: Frozen semen . ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. gfs-topgenetik.de, 2007; Retrieved November 7, 2008.
- ↑ Rhinoceros: Successful insemination with frozen semen . lifegen.de, 2007; Retrieved November 7, 2008
- ↑ Production and export of frozen semen from the black-brown mountain sheep . ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. sbs-bnp.ch; Retrieved November 7, 2008
- ↑ Animal health certificate for equine semen . ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. bmelv.de; Retrieved November 7, 2008
- ^ For the first time, panda offspring made from frozen semen . nzz.ch; Retrieved July 27, 2009
