Approximately 200 dairy herds will be required to take part and each of these herds will have to use 60 straws (30 sexed and 30 normal) from five different high-EBI sires. In total, we understand there are 11 sires in the trial (see Table 1). The trial will use the semen used on cows only, not maiden heifers. Scientists claim the technology of sexed semen has improved since the last field trial completed in 2013. It is for this reason ICBF, Teagasc and partner AI companies (Dovea Genetics, Munster Cattle Breeding Group and Progressive Genetics) are proposing to undertake this field research trial in 2018 to establish the relative performance of sexed semen compared with conventional (non-sexed) semen.