SALVAGE OF OOCYTES FROM STERILE GENETICALLY VALUABLE COWS, RESULTING IN THE BIRTH OF A CALF

The objective of this study was to determine the possible application of in vitro fertilization techniques for calf production in incurable sterility patients or in involuntary cull cows. Ten sterile or fatally injured dams of high genetic value were submitted to in vitro fertili zation procedures. Ovaries were recovered after slaughter in eight ani mals or after ovariectomy in two cows. A total of 261 oocytes were obt ained and matured in vitro. Frozen-thawed sperm from eight different b ulls of high breeding value (selected to match with one particular cow ) was separated with Percoll and used for in vitro fertilization in th e presence of heparin. Seventy four embryos started to cleave and 7 da ys post-insemination, 13 transferable embryos were obtained. Eleven em bryos were transferred fresh into nine recipients and produced two pre gnancies. One pregnant recipient died of hydro-allantois, the other de livered a live bull calf 288 days after in vitro fertilization.