1. Introduction
It has been well established in horses and cattle that dam size affects birth weight of newborn (Hunter, 1956, Joubert, 1956 and Allen et al., 2002). A recent, study (Sharma et al., 2012a) reported that large genotype Suffolk lambs were lighter and smaller when born to small genotype Cheviot dams, compared to Suffolk lambs born to Suffolk dams. Conversely, neither birth weight nor body dimensions of small genotype Cheviot lambs differed when born to Suffolk or Cheviot dams. Some studies have also indicated that mid-gestational uterine environment affects foetal development (Jenkinson et al., 2007 and Sharma et al., 2012b). However the effects of early uterine environment on embryonic development are currently unknown. This information is of importance for understanding the mechanisms through which uterine environment affects foetal growth.