ASSESSMENT OF FERTILIZING ABILITY OF GOAT SPERMATOZOA BY IN-VITRO FERTILIZATION OF CATTLE AND SHEEP INTACT OOCYTES

Intacy oocytes of cattle and sheep were used to study factors that aff ect the in vitro fertilizing (IVF) ability of goat spermatozoa in vitr o. Oocytes were matured in Medium 199 plus estrous sheep serum. Fresh semen was incubated for 4 h at room temperature and spermatozoa were t hen resuspended in medium Talp plus serum, and were incubated further for 1 h at 39 degrees C in 5% CO2 in air. Later, spermatozoa were resu spended in Talp plus serum and heparin and were then incubated in micr odrops until oocytes were matured. In Experiment 1, the pattern of spe rm penetration in matured cattle, sheep and goat oocytes was studied u sing either residual or standard experimental levels of calcium in the IVF medium. In Experiment 2, the same pattern was studied now by eval uating the sperm penetration rate in cattle oocytes under increasing c oncentrations of heparin in the IVF medium and then comparing them wit h those obtained using sheep and goat oocytes. As in Experiment 2, in Experiment 3 the pattern of sperm penetration was studied using increa sing concentrations of caffein in the IVF medium. Gametes were incubat ed for 18 h, and penetration rates were assessed by the presence of pr onuclei and sperm tail in the oocyte cytoplasm. The results indicate t hat 1) the sperm penetration rate in intact cattle, sheep and goat ooc ytes follows a pathway that depends on calcium; 2) heparin improves th e sperm penetration rate in cattle, sheep and goat oocytes following a comparable pattern; and 3) caffeine depresses the sperm penetration r ate in cattle, sheep and goat oocytes, but the pattern of inhibition d epends on the genetic origin of the oocytes. The results also suggest that cattle and sheep intact oocytes can be used to assess the fertili zing ability of goat spermatozoa.