“…It has been observed that changes in the synthesis and secretion of oviducal polypeptides are associated with the oestrous cycle in cattle (Malayer et al, 1988) and sheep (Buhi et al, 1989). Indeed, the oviducal cell co-culture system has been extensively used for early embryos in dom¬ estic species, including cows (Eyestone & First, 1989;Pollard et al, 1989;Ellington et al, 1990a, b, c), pigs (White et al, 1989), sheep (Gandolfi & Moor, 1987), goats (Sakkas et al, 1989), and horses (Ball & Altschul, 1990;Weber et al, 1990), as well as in humans (Sathananthan et al, 1990). Oviducal epithelial cells have also been shown to maintain the motility and fertilizing capacity of bovine spermatozoa in vitro (Pollard et al, 1991).…”