hormone which can enhance bovine embryo development in vitro (de Moraes et al., 1997) and

has been reported to increase birth rate in mice (Sjoblom et al., 2005).

 Future experiments evaluating the effects of IGF-1 on embryo survival should focus, in

more depth, on the molecular and cellular effects of IGF-1 supplementation during embryo

culture. In particular, the evaluation of gene expression and methylation patterns at different

time points, such as at day 7 and d 25, may provide more insight in to the actions of IGF-1 to

promote embryo survival between day 21 and day 28 of gestation. In addition, the use of more

advanced techniques, such as microarray or SELDI-TOF to evaluate IGF-1 actions on a larger

scale could be beneficial in identifying markers of embryo survival. Such markers could

potentially be useful in developing assays to select embryos prior to transfer.