Comparison of fertility and embryo mortality following artificial insemination of common duck females (Anas Platyrhynchos) with semen from common or Muscovy (Cairina Moschata) drakes

Comparison of early embryo mortality (EEM) between mule and common duck eggs indicated that increased levels of EEM in mule embryos corresponded to Stages II-IV of the Eyal-Giladi and Kochav classification (EGK). While a similar age-dependent increase in early embryo mortality was observed in eggs from both genetic origins during the latter periods of the reproductive season, it was also established that embryo mortality due to parental age was related rather to Stages X-XIV of the EGK classification in eggs from both genetic origins. It is concluded that the relative subfertility of mule compared to common duck eggs is probably the consequence of a more intense rate of selection of heterologous than homologous spermatozoa occurring in the vaginal portion of the oviduct while the causal origins of EEM in mule duck eggs can at least in part be identified on the basis of precise staging (by stereomicroscopy) of dead embryos.