Effect of embryo transfer technique on the likelihood of pregnancy in the mare: a comparison of conventional and Wilsher's forceps-assisted transfer

Abstract

The aim of this study was to compare the success of embryo transfer (ET) performed by veterinarians with different degrees of experience using one of two ET techniques. Over three years, 179 embryos were transferred by three operators with moderate to high experience using a 'conventional' manual technique, and 170 embryos were transferred by four operators with little or no previous ET experience using a 'Wilsher' technique (Polansky speculum and Wilsher's cervical forceps). The pregnancy status of recipient mares at the first pregnancy diagnosis and the embryo loss by the last examination were compared between groups and within group among operators. More recipients became pregnant (P<0.005) following ET with the Wilsher technique (157/170; 92.3 per cent) than with the conventional technique (127/179; 70.9 per cent), while the incidence of pregnancy loss did not differ between the groups (9.1 v 7.9 per cent, respectively). For the conventional technique, there was a significant operator effect (P<0.01) on the percentage of pregnant recipients at the first examination (50.9-79.7 per cent); no operator effect was apparent for the Wilsher technique (90.9-93.4 per cent). In conclusion, the Wilsher technique yielded high pregnancy rates (>90 per cent).