Transfer of exotic equine embryos to domestic horses and donkeys

Abstract

Summary A total of 43 non‐surgical embryo recoveries performed on two Przewalski's horse mares (Equus przewalski) and two Grant's zebra mares (E burchelli) yielded 11 Przewalski and 14 zebra embryos. Surgical transfer of nine Przewalski embryos to domestic pony recipient mares resulted in seven (78 per cent) extraspecific pregnancies. Two of these recipient mares gave birth to live foals on Days 324 and 329 of gestation respectively and two are at Days 175 and 166 respectively at the time of writing; three conceptuses were resorbed at various times between Days 20 and 100. Non‐surgical transfer of two Przewalski's horse embryos and flank surgical transfer of one other Przewalski's horse embryo to domestic mares failed to establish any pregnancy. Surgical transfer of five zebra embryos to domestic pony recipients resulted in three (60 per cent) extraspecific pregnancies; one conceptus was resorbed between Days 61 and 70 and the other two are at Days 190 and 201 respectively at the time of writing. Surgical transfer of seven zebra embryos to jenny donkeys gave two (29 per cent) extraspecific pregnancies; one conceptus was resorbed between Days 53 and 79 and the other foal was born prematurely on Day 292 and lived for only 3 h. Non‐surgical transfer of one Day 10 zebra embryo to a jenny donkey did not result in a pregnancy. These experiments demonstrated that it is possible repeatedly to recover embryos non‐surgically from sedated wild equids and transfer them successfully to domestic horse and donkey recipients. The production of such extraspecific pregnancies by embryo transfer has considerable value as a research tool and the technique should also prove valuable in the future for maximising the reproductive potential of endangered equine species in captivity.

Gross Anatomy of the Female Genital Organs of the Domestic Donkey (Equus asinusLinné, 1758)

“…However, when browsing scientific databases very little information on the morphology of the asinine reproductive tract is available, even if some experimental work has been done that should have required exact knowledge of the jenny’s (reproductive) anatomy as a prerequisite (e.g. Allen, 1982; Kydd et al., 1985; Allen et al., 1987; Pugh, 2002).…”

Embryo transfer in the mare was introduced 30 years ago.

“…των πόνυ της Σκύ ρου. Ήδη, η μέθοδος έχει χρησιμοποιηθεί για τη διάσω ση φυλών άγριων ιπποειδών (μεταφορά εμβρύων ίππου Πρεβάλσκι και ζέβρας Γκραντ σε φοράδες πόνυ) 3 . Η μεταφορά εμβρύου μεταξύ συγγενικών ειδών ιππο ειδών χρησιμοποιείται ως μέσο έρευνας προβλημάτων α ναπαραγωγής.…”

“…Οι Fleury και συν. πρό τειναν τη χρήση 500, 250 και 250 ml για την 1η, 2η και 3η έκπλυση της μήτρας, αντίστοιχα 3 . Ωστόσο, η ποσότητα του υγρού έκπλυσης δε θα πρέπει να προκαθορίζεται, δεδο μένου ότι είναι ανάλογη του μεγέθους της μήτρας του ζ(όου.…”

Breeding or Assisted Reproduction? Relevance of the Horse Model Applied to the Conservation of Endangered Equids

“…donkey embryo in horse). This means that domestic horses, donkeys or mules (some of which can support pregnancy after embryo transfer; review, Allen et al 2011) can be used as a recipient for exotic equine embryos such as those of Przewalski's horse and Grant's zebra (Kydd et al 1985;Summers et al 1987). This may be a useful strategy when combining assisted reproduction with GRB.…”

“…The availability of appropriate surrogate mothers is not a limitation to the use of embryo transfer in endangered horse breeds or even for many wild equids; the domestic horse has been proven to be a suitable recipient for either. Pregnancy rates for Przewalski's horse-to-horse and Grant's zebra-to-horse extraspecific pregnancies were 64 and 60, respectively, with three live Przewalski's horse and one live zebra foal being born (27% and 20% from embryos transferred) ( Table 2: Kydd et al 1985;Summers et al 1987;Allen et al 2011). Donkey recipients seem to be less suitable that only two pregnancies occurred and neither was carried to term (Table 2).…”