Current status and prospects of the application of biotechnologies of reproduction in cattle

The A. I. technology is the oldest but still most meaningful reproduction technology. Actually, approx. 4.8 million first inseminations are carried out in Germany per year. The number of inseminations has decreased due to increasing performances and fixed amounts of delivery for milk within the last years by 2 to 4 % per year. Embryo transfer has been used in cattle breeding for about 25 years. The production of breeding bull calves as well as the breeding work with cow families is its central application. On average 6 to 7 transferable embryos per donor are recovered after superovulatory treatment, A. I. and embryo recovery in Holstein cattle. Approximately half of the embryos is transferred fresh whereas the other half is deep-frozen. The cryo-preservation of embryos is routinely carried out. Another reproduction biotechnology, the in vitro production of embryos has been introduced into practice. The method is used primarily to shorten the generation interval. Aspects of the method are continuously investigated to improve the efficiency of the complete method. On the other hand, cloning technology does not currently have practical significance me cattle production. The main emphasis of the application of the method is rather on the production of transgenic animals. The efficiency of the method altogether is low. Of the different methods of sexing of embryos the detection of Y chromosome specific DNA has gained acceptance since the beginning of the nineties. The percentage of correct diagnoses is over 90 %. In the field of sperm sorting the flow cytometric detection of the of DNA in X or Y chromosome bearing spermatozoa is currently the only reliable method. The enrichment of sperm cells with an X or Y chromosome in the appropriate groups is over 90 %. Only limited data about pregnancy rates after insemination of sorted spermatozoa under field conditions are available. Results show that the pregnancy rates are about 15-20 % below those in the control groups.