Biotechnology for increasing cattle production
1994
Pavasuthipaisit, K. | Kitiyanant, Y. | Tocharus, C. (Mahidol Univ., Bangkok (Thailand). Faculty of Science. Dept. of Anatomy)
Related embryo transfer technology to improve the cattle quality and productivity while at the same time reducing cost has been developed in the present study. The mass production of embryos from cattle ovaries utilizing in vitro oocyte maturation (IVM), fertilization (IVF) followed by in vitro culture (IVC) of these early stage embryos to a transferable stage was reported. A large number of cattle embryos produced by these methods have been non-surgically transferred to native recipient cows and pregnancies as well as normal calves born were achieved. Aspirating follicles from ovaries of slaughtered animals is the common procedure to obtain oocytes for IVM but represents a non repeatable approach. A repeatable recovery of immature oocytes from valuable donor cows guided by ultrasound was successfully performed. This most effective methods provide large number of oocytes for large scale IVM/IVF/IVC from valuable living donor cows. In the bull, sperm microinjection is an efficient way to employ genetically superior but biologically inferior male gametes to increase cattle production. The aim of the present project was to fertilize and develop cattle embryos in vitro after microinjection of capacitated sperm either directly into the ooplasm or under the zona pellucida. The embryonic development to the hatch blastocyst stage was demonstrated after microinjection of sperm into either the ooplasm or the subzonal space of in vitro matured oocytes. The mass production of embryos combined with the ability to select the desired sex will insure the production of the specific sex and further facilitate the development of cattle production. As sperm determine the sex of the offspring the present study has employed the technique of flow cytometry and cell sorting to separate cattle X- and Y- bearing sperm. In addition the preimplantation stage embryos were sexed by H-Y immunofluorescence and DNA probes complementary to highly repetitive regions specifically to the Y-chromosomes.
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