STERILITY IN CATTLE OF HIGH GENETIC VALUE - CHANCE OF OBTAINING OFFSPRING IS ASSURED THANKS TO IN-VITRO FERTILIZATION

This study describes the results of in vitro fertilization (IVF) in 21 sterile donor cows of high genetic value, 16 of which had been treate d with FSH before slaughter in an attempt to improve oocyte quality. A limited number of breeding sires (n=5) with a history of good fertili zation results in vitro were used. A mean of 5.7+/-1.1 transferable em bryos and 1.2+/-03 pregnancies per donor cow was obtained. Finally 15 calves were born and five pregnancies are currently ongoing and beyond five months. Eleven donors yielded at least one calf. Birth weights o f calves were rather high (50.2+/-4.6 kg for Holstein and 51.1+/-3.1 k g for Belgian Blue breeds). The sex ratio was 87 % (males/total). In c onclusion it can be stated that a cattle breeder has a 50 % chance of obtaining a calf from a sterile dam using IVF after slaughter. Problem s with heavy calves and a deviant sex ratio have to be solved by impro ving culture conditions for bovine embryos.