Effect of site of transfer on pregnancy and twinning rates following bilateral egg transfer in the cow

Abstract

High pregnancy and egg survival rates can be achieved following surgical egg transfer techniques in the cow (Rowson, Lawson & Moor, 1971; Sreenan, Beehan & Mulvehill, 1975). The application of such techniques under farm conditions requires the development of simple non-surgical transfer techniques, but attempts to develop such procedures have so far resulted in pregnancy and egg survival rates much lower than those achieved by surgical techniques (Rowson & Moor, 1966; Sreenan, 1975; Lawson, Rowson, Moor & Tervit, 1975; Boland, Crosby & Gordon, 1975), perhaps because of egg expulsion or the introduction of uterine infection (Rowson, Lamming & Fry, 1953; Rowson, Bennett & Harper, 1964). More recent work indicates a trend towards improved pregnancy rates when non-surgical transfers are carried out between Days 6 to 9 of the oestrous cycle rather than earlier (Lawson et al., 1975; Sreenan, 1975).