Perinatal lamb mortality remains a major economic and welfare concern in sheep farming with 80-90% of pre-weaning lamb losses occur in the immediate postnatal period (Haughey, 1993). One of the predominant factors in the death of neonatal lambs is failure of ewe-lamb bonding leading to delay or lack of sucking. Successful sucking requires the co-ordinated expression of appropriate behaviour from both the ewe and lamb. Previously we have demonstrated an interaction between ewe and lamb breed in the rate of successful sucking (Dwyer et al., 1996) with Blackface lambs having a higher rate than Suffolk lambs but also a higher rate with Suffolk ewes than with Blackface ewes. In the present study we investigated the role of ewe responses to lamb sucking attempts in determining the sucking success of neonatal lambs.