IN-VITRO FERTILIZATION OF CATTLE AND SHEEP FOLLICULAR OOCYTES BY GOATSPERMATOZOA

The study compared efficiency of goat spermatozoa to penetrate cattle and sheep intact follicular oocytes, and evaluated effect of cumulus c ells on the ability of sperm to penetrate heterologous oocytes. Rumina nt cumulus-oocyte complexes (COC) were obtained by aspiration of ovari an follicles and were matured by culturing them in medium 199 plus goa t serum in microdrops under paraffin oil for 24 h. Fresh semen was col lected by artificial vagina, incubated for 4 h at room temperature, wa shed, and spermatozoa were then suspended in Talp medium plus goat ser um and treated for capacitation by using incubation at 39-degrees-C an d heparin. In the first experiment, goat, cattle and sheep matured ooc ytes were incubated in goat sperm preparation, whereas in the second e xperiment, cattle and sheep oocytes either partially (cumulus enclosed oocytes = +) or totally denuded from granulosa cells (denuded oocytes = -) were added to the prepared spermatozoa. Fertilization rates obta ined in the first experiment (goat sperm-goat oocytes: 91.3%; goat-cat tle: 82.7%; and goat-sheep: 79.8%, P > 0.05), showed that goat sperm w ere highly efficient in penetrating cattle and sheep oocytes as compar ed with homologous fertilization, and that goat sperm penetrated equal ly well cattle and sheep oocytes. Fertilization rates from the second experiment (cattle oocytes: +74.0%, -88.89%; sheep oocytes: + 68.42%, -78.85%, P > 0.05), showed that cumulus cells did not modify the abili ty of goat spermatozoa to penetrate heterologous oocytes.