Fertility following egg transfer in the cow; effect of method, medium and synchronization of oestrus.

Abstract

Summary. A total of ninety-two heifers was used in a series of four experiments designed to investigate the effect of method of egg recovery, transfer, storage medium and degree of synchronization between donor and recipient compatible with fertility. Experiments 1 and 2 involved the transfer of thirty-three eggs in homologous serum to eighteen recipients. In half of these, the eggs were transferred surgically and in the other half non-surgically. No pregnancies resulted from these transfers. In Experiments 3 and 4, a total of seventy-six eggs was transferred to forty recipient heifers using TCM 199 as the transfer and storage medium. Twenty of these transfers were made surgically, the eggs also being recovered by surgical means in eleven cases and by slaughter in nine. The pregnancy rate obtained was 91% for surgically recovered and transferred eggs and 33% for eggs recovered at slaughter and then transferred surgically. The remaining twenty animals received eggs, half of which were recovered surgically and half at slaughter, and all then transferred by non-surgical means. It is concluded that homologous serum is an unsuitable medium for egg transfer but that TCM 199 is highly satisfactory. The recovery of eggs from slaughtered animals appears less satisfactory than if they are recovered in vivo. A degree of variation from exact synchronization of \m=+-\2days can be tolerated.