Equine Embryo Transfer

  • H. SiemeEmail author
  • J. Rau
  • D. Tiedemann
  • H. Oldenhof
  • L. Barros
  • R. Sanchez
  • M. Blanco
  • G. Martinsson
  • C. Herrera
  • D. Burger


Embryo transfer has become a commonly used procedure in equine breeding worldwide. It allows for efficient use of valuable mares and mares in athletic competition. In addition, mares with reproductive problems can donate embryos to healthy recipients. This review describes techniques for embryo collection and transfer to the recipient, methods of transportation and cryopreservation, and superovulation procedures. Effects of specific procedures on success rates for embryo collection and pregnancies are discussed, as well as factors affecting the resulting offspring. Furthermore, an outlook is given on recent biotechnological technologies like preimplantation diagnostics and in vitro embryo production.


Equine Embryo transfer Superovulation Cryopreservation Vitrification Reproductive biotechnologies 


  1. Allen WR (ed) (1982) Embryo transfer in the horse. CRC Press, Boca Raton, FLGoogle Scholar
  2. Allen WR (2005) The development and application of the modern reproductive technologies to horse breeding. Reprod Domest Anim 40:310–329CrossRefPubMedGoogle Scholar
  3. Allen WR, Rowson LEA (1972). Transfer of ova between horses and donkeys. In: Proc., 7th int. congress on animal reproduction and artificial insemination, 6–9 June 1972, Munich, pp 484–487Google Scholar
  4. Allen WR, Wilsher S, Tiplady C, Butterfield RM (2004) The influence of maternal size on pre- and postnatal growth in the horse: III. Postnatal growth. Reproduction 127:67–77CrossRefPubMedGoogle Scholar
  5. Barfield JP, McCue PM, Squires EL, Seidel GE Jr (2009) Effect of dehydration prior to cryopreservation of large equine embryos. Cryobiology 59:36–41CrossRefPubMedPubMedCentralGoogle Scholar
  6. Battut I, Colchen S, Fieni F, Tainturier D, Bruyas JF (1997) Success rates when attempting to nonsurgically collect equine embryos at 144, 156 or 168 hours after ovulation. Equine Vet J Suppl (25):60–62Google Scholar
  7. Betteridge KJ, Eaglesome MD, Mitchell D, Flood PF, Beriault R (1982) Development of horse embryos up to twenty two days after ovulation: observations on fresh specimens. J Anat 135:191–209PubMedPubMedCentralGoogle Scholar
  8. Briant C, Toutain PL, Ottogalli M, Magallon T, Guillaume D (2004) Kinetic studies and production rate of equine (e) FSH in ovariectomized pony mares. Application to the determination of a dosage regimen for eFSH in a superovulation treatment. J Endocrinol 182:43–54CrossRefPubMedGoogle Scholar
  9. Bruyas JF, Sanson JP, Battut I, Fieni F, Tainturier D (2000) Comparison of the cryoprotectant properties of glycerol and ethylene glycol for early (day 6) equine embryos. J Reprod Fertil Suppl (56):549–560Google Scholar
  10. Burger D, Schauer SN, Waegeli S, Aurich C, Gerber V, Thun R (2008) Influence of the recipient mare on size and character traits of adult offspring in a warmblood embryo transfer program—preliminary results, 7. Havemeyer embryo transfer symposium, Cambridge, July 2008Google Scholar
  11. Campbell ML (2014) Embryo transfer in competition horses: managing mares and expectations. Equine Vet Educ 26:322–327CrossRefPubMedPubMedCentralGoogle Scholar
  12. Carnevale EM, Squires EL, Mckinnon AO (1987) Comparison of Ham’s F10 with CO2 or Hepes buffer for storage of equine embryos at 5 C for 24 H. J Anim Sci 65:1775–1781CrossRefPubMedGoogle Scholar
  13. Carnevale EM, Ramirez RJ, Squires EL, Alvarenga MA, Vanderwall DK, McCue PM (2000) Factors affecting pregnancy rates and early embryonic death after equine embryo transfer. Theriogenology 54:965–979CrossRefPubMedGoogle Scholar
  14. Carney NJ, Squires EL, Cook VM, Seidel GE Jr, Jasko DJ (1991) Comparison of pregnancy rates from transfer of fresh versus cooled, transported equine embryos. Theriogenology 36:23–32CrossRefPubMedGoogle Scholar
  15. Chavatte-Palmer P, Robles M, Tarrade A, Duranthon V (2016) Gametes, embryos and their epigenome: considerations for equine embryo technologies. J Equine Vet Sci 41:13–21CrossRefGoogle Scholar
  16. Choi YH, Love CC, Love LB, Varner DD, Brinsko S, Hinrichs K (2002) Developmental competence in vivo and in vitro of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection with fresh or frozen-thawed spermatozoa. Reproduction 123:455–465CrossRefPubMedGoogle Scholar
  17. Choi YH, Velez IC, Riera FL, Roldan JE, Hartman DL, Bliss SB, Blanchard TL, Hayden SS, Hinrichs K (2011) Successful cryopreservation of expanded equine blastocysts. Theriogenology 76:143–152CrossRefPubMedGoogle Scholar
  18. Combarnous Y, Richard F, Martinat N (1998) Mammalian follicle stimulating hormone receptors and their ligands. Eur J Obstet Gynecol Reprod Biol 77:125–130CrossRefPubMedGoogle Scholar
  19. Cuervo-Arango J, Claes AN, Ruijter-Villani M, Stout TA (2017) Likelihood of pregnancy after embryo transfer is reduced in recipient mares with a short preceding oestrus. Equine Vet J 50(3):386–390CrossRefPubMedGoogle Scholar
  20. Czlonkowska M, Boyle MS, Allen WR (1985) Deep freezing of horse embryos. J Reprod Fertil 75:485–490CrossRefPubMedGoogle Scholar
  21. Day F (1940) Clinical and experimental observations on reproduction in the mare. J Agric Sci Camb 30:244–261CrossRefGoogle Scholar
  22. Dell’aquila ME, Cho YS, Minoia P, Traina V, Fusco S, Lacalandra GM, Maritato F (1997) Intracytoplasmic sperm injection (ICSI) versus conventional IVF on abattoir-derived and in vitro-matured equine oocytes. Theriogenology 47:1139–1156CrossRefPubMedGoogle Scholar
  23. DeLuca CA, McCue PM, Patten ML, Squires EL (2008) Comparison of three doses of reFSH for superovulation of mares. Theriogenology 70:587–588CrossRefGoogle Scholar
  24. Diaz F, Bondiolli K, Paccamonti D, Gentry GT (2016) Cryopreservation of Day 8 equine embryos after blastocyst micromanipulation and vitrification. Theriogenology 85:894–903CrossRefPubMedGoogle Scholar
  25. Eldridge-Panuska WD, Di Brienza VC, Seidel GE Jr, Squires EL, Carnevale EM (2005) Establishment of pregnancies after serial dilution or direct transfer by vitrified equine embryos. Theriogenology 63:1308–1319CrossRefPubMedGoogle Scholar
  26. Ferreira JC, Meira C, Papa FO, Landin E Alvarenga FC, Alvarenga MA, Buratini J (1997) Cryopreservation of equine embryos with glycerol plus sucrose and glycerol plus 1,2-propanediol. Equine Vet J Suppl:88–93Google Scholar
  27. Ferris RA, McCue PM, Trundell DA, Morrissey JK, Barfield JP (2016) Vitrification of large equine embryos following manual or micromanipulator-assisted blastocoele collapse. J Equine Vet Sci 41:64–65CrossRefGoogle Scholar
  28. Flood PF, Betteridge KJ, Diocee MS (1982) Transmission electron microscopy of horse embryos 3-16 days after ovulation. J Reprod Fertil Suppl 32:319–327PubMedGoogle Scholar
  29. Fortune JA, Kimmich TL (1993) Purified pig FSH increases the rate of double ovulations in the mare. Equine Vet J Suppl 15:95–98Google Scholar
  30. Galli C, Crotti G, Notari C, Turini P, Duchi R, Lazzari G (2001) Embryo production by ovum pick up from live donors. Theriogenology 55:1341–1357CrossRefPubMedGoogle Scholar
  31. Galli C, Colleoni S, Duchi R, Lagutina I, Lazzari G (2007) Developmental competence of equine oocytes and embryos obtained by in vitro procedures ranging from in vitro maturation and ICSI to embryo culture, cryopreservation and somatic cell nuclear transfer. Anim Reprod Sci 98:39–55CrossRefPubMedGoogle Scholar
  32. Galli C, Duchi R, Colleoni S, Lagutina I, Lazzari G (2014) Ovum pick up, intracytoplasmic sperm injection and somatic cell nuclear transfer in cattle, buffalo and horses: from the research laboratory to clinical practice. Theriogenology 81:138–151CrossRefPubMedGoogle Scholar
  33. Ginther OJ, Bergfelt DR (1990) Effect of GnRH treatment during the anovulatory season on multiple ovulation rate and on follicular development during the ensuing pregnancy in mares. J Reprod Fertil 88:119–126CrossRefPubMedGoogle Scholar
  34. Greco GM, Burlamaqui FG, Pinna AE, Queiroz FR, Cunha MS, Brandão FZ (2012) Use of long-acting progesterone to acyclic embryo recipient mares. Rev Bras Zootec Anim 41(3):607–611CrossRefGoogle Scholar
  35. Guignot F, Reigner F, Perreau C, Tartarin P, Babilliot JM, Bed'hom B, Vidament M, Mermillod P, Duchamp G (2015) Preimplantation genetic diagnosis in Welsh pony embryos after biopsy and cryopreservation. J Anim Sci 93:5222–5231CrossRefPubMedGoogle Scholar
  36. Handler J, Konigshofer M, Kindahl H, Schams D, Aurich C (2003) Secretion patterns of oxytocin and PGF2alpha-metabolite in response to cervical dilatation in cyclic mares. Theriogenology 59:1381–1391CrossRefPubMedGoogle Scholar
  37. Hartman DL (2011) Embryo transfer. In: McKinnon AO, Squires EL, Vaala WE, Varner DD (eds) Equine reproduction, 2nd edn. Blackwell Publishing Ltd., Ames, IAGoogle Scholar
  38. Herrera C, Morikawa MI, Bello MB, Von Meyeren M, Centeno JE, Dufourq P, Martinez MM, Llorente J (2014) Setting up equine embryo gender determination by preimplantation genetic diagnosis in a commercial embryo transfer program. Theriogenology 81:758–763CrossRefPubMedGoogle Scholar
  39. Hinrichs K (2010) In vitro production of equine embryos: state of the art. Reprod Domest Anim 45(Suppl 2):3–8CrossRefPubMedGoogle Scholar
  40. Hofferer S, Duchamp G, Palmer E (1991) Ovarian response in mares to prolonged treatment with exogenous equine pituitary gonadotrophins. J Reprod Fertil Suppl 44:341–349PubMedGoogle Scholar
  41. Iuliano MF, Squires EL, Cook VM (1985) Effect of age of equine embryos and method of transfer on pregnancy rate. J Anim Sci 60:258–263CrossRefPubMedGoogle Scholar
  42. Jacob JC, Haag KT, Santos GO, Oliveira JP, Gastal MO, Gastal EL (2012) Effect of embryo age and recipient asynchrony on pregnancy rates in a commercial equine embryo transfer program. Theriogenology 77:1159–1166CrossRefPubMedGoogle Scholar
  43. Jasko DJ (2002) Comparison of pregnancy rates following non-surgical transfer of day 8 embryos using various transfer devices. Theriogenology 58:713–716CrossRefGoogle Scholar
  44. Kask K, Odensvik K, Kindahl H (1997) Prostaglandin F2alpha release associated with an embryo transfer procedure in the mare. Equine Vet J 29:286–289CrossRefPubMedGoogle Scholar
  45. Kelley DE, Gibbons JR, Smith R, Vernon KL, Pratt-Phillip SE, Mortensen CJ (2011) Exercise affects both ovarian follicular dynamics and hormone concentrations in mares. Theriogenology 76:615–622CrossRefPubMedGoogle Scholar
  46. Koblischke P, Kindahl H, Budik S, Aurich J, Palm F, Walter I, Kolodziejek J, Nowotny N, Hoppen HO, Aurich C (2008) Embryo transfer induces a subclinical endometritis in recipient mares which can be prevented by treatment with non-steroid anti-inflammatory drugs. Theriogenology 70:1147–1158CrossRefPubMedGoogle Scholar
  47. Legrand E, Bencharif D, Battut I, Taintuier D, Bruyas JF (1999) Horse embryo freezing: influence of thickness of the capsule. In: Proceedings of the 15th scientific meeting of the European Embryo Transfer Association, Lyon, France, pp 184–185Google Scholar
  48. Love CC, Noble JK, Standridge SA, Bearden CT, Blanchard TL, Varner DD, Cavinder CA (2015) The relationship between sperm quality in cool-shipped semen and embryo recovery rates in horses. Theriogenology 84:1587–1593CrossRefPubMedGoogle Scholar
  49. Marinone AI, Losinno L, Fumuso E, Rodriguez EM, Redolatti C, Cantatore S, Cuervo-Arango J (2015) The effect of mare’s age on multiple ovulation rate, embryo recovery, post-transfer pregnancy rate, and interovulatory interval in a commercial embryo transfer program in Argentina. Anim Reprod Sci 158:53–59CrossRefPubMedGoogle Scholar
  50. McCue PM (1996) Superovulation. Vet Clin North Am Equine Pract 12:1–11CrossRefPubMedGoogle Scholar
  51. McCue PM, Squires EL (2015) Equine embryo transfer, 1st edn. CRC Press, Boca Raton, FLCrossRefGoogle Scholar
  52. McCue PM, Hughes JP, Lasley BL (1993) Effect on ovulation rate of passive immunisation of mares against inhibin. Equine Vet J 25:103–106CrossRefGoogle Scholar
  53. McCue PM, Niswender KD, Macon KA (2003) Modification of the flush procedure to enhance embryo recovery. J Equine Vet Sci 23:336–337CrossRefGoogle Scholar
  54. McCue PM, Ferris RA, Lindholm AR, DeLuca CA (2010) Embryo recovery procedures and collection success: results of 492 embryo-flush attempts. In: Proceedings of the 56th annual convention of the American Association of Equine PractitionersGoogle Scholar
  55. McCue PM, DeLuca CA, Wall JJ (2011) Cooled transported embryo technology. In: McKinnon AO, Squires EL, Vaala WE, Varner DD (eds) Equine reproduction, 2nd edn. Wiley-Blackwell, Ames, IA, pp 2880–2886Google Scholar
  56. McKinnon AO, Squires EL (1988a) Equine embryo transfer. Vet Clin North Am Equine Pract 4:305–333Google Scholar
  57. McKinnon AO, Squires EL (1988b) Morphologic assessment of the equine embryo. J Am Vet Med Assoc 192:401–406Google Scholar
  58. McKinnon AO, Brown RW, Pashen RL, Greenwood PE, Vasey JR (1992) Increased ovulation rates in mares after immunisation against recombinant bovine inhibin alpha-subunit. Equine Vet J 24:144–146Google Scholar
  59. Meyers-Brown G, Bidstrup LA, Famula TR, Colgin M, Roser JF (2011) Treatment with recombinant equine follicle stimulating hormone (reFSH) followed by recombinant equine luteinizing hormone (reLH) increases embryo recovery in superovulated mares. Anim Reprod Sci 128:52–59CrossRefPubMedGoogle Scholar
  60. Mortensen CJ, Choi YH, Hinrichs K, Ing NH, Kraemer DC, Vogelsang SG, Vogelsang MM (2009) Embryo recovery from exercised mares. Anim Reprod Sci 110:237–244CrossRefPubMedGoogle Scholar
  61. Moussa M, Tremoleda JL, Duchamp G, Bruyas JF, Colenbrander B, Bevers MM, Daels PF (2004) Evaluation of viability and apoptosis in horse embryos stored under different conditions at 5° C. Theriogenology 61:921–932CrossRefPubMedGoogle Scholar
  62. Moussa M, Bersinger I, Doligez P, Guignot F, Duchamp G, Vidament M, Mermillod P, Bruyas JF (2005) In vitro comparisons of two cryopreservation techniques for equine embryos: slow-cooling and open pulled straw (OPS) vitrification. Theriogenology 64:1619–1632CrossRefPubMedGoogle Scholar
  63. Nagao JF, Neves Neto JR, Papa FO, Alvarenga MA, Freitas-Dell’Aqua CP, Dell’Aqua JA (2012) Induction of double ovulation in mares using deslorelin acetate. Anim Reprod Sci 136:69–73CrossRefPubMedGoogle Scholar
  64. Newcombe JR (1995) Incidence of multiple ovulation and multiple pregnancy in mares. Vet Rec 137:121–123CrossRefPubMedGoogle Scholar
  65. Niswender KD, Alvarenga MA, McCue PM, Hardy QP, Squires EL (2003) Superovulation in cycling mares using equine follicle stimulating hormone (eFSH). J Equine Vet Sci 23:497–500CrossRefGoogle Scholar
  66. Oberstein N, O’Donovan MK, Bruemmer JE, Seidel GE Jr, Carnevale EM, Squires EL (2001) Cryopreservation of equine embryos by open pulled straw, cryoloop, or conventional slow cooling methods. Theriogenology 55:607–613CrossRefPubMedGoogle Scholar
  67. Oguri N, Tsutsumi Y (1972) Non-surgical recovery of equine eggs, and an attempt at non-surgical egg transfer in horses. J Reprod Fertil 31:187–195CrossRefPubMedGoogle Scholar
  68. Oguri N, Tsutsumi Y (1974) Non-surgical egg transfer in mares. J Reprod Fertil 41:313–320CrossRefPubMedGoogle Scholar
  69. Okada CTC, Segabinazzi LG, Crespilho AM, Dell’Aqua JA Jr, Alvarenga MA (2018) Effect of the flunixin meglumine on pregnancy rates in an equine embryo transfer program. J Equine Vet Sci 62:40–43CrossRefGoogle Scholar
  70. Oliveira Neto IV, Canisso IF, Segabinazzi LG, Dell’Aqua CPF, Alvarenga MA, Papa FO, Dell’Aqua JA Jr (2018) Synchronization of cyclic and acyclic embryo recipient mares with donor mares. Anim Reprod Sci 190:1–9CrossRefPubMedGoogle Scholar
  71. Ousey JC, Rossdale PD, Fowden AL, Palmer L, Turnbull C, Allen WR (2004) Effects of manipulating intrauterine growth on postnatal adrenocortical development and other parameters of maturity in neonatal foals. Equine Vet J 36:616–621CrossRefPubMedGoogle Scholar
  72. Panzani D, Rota A, Pacini M, Vannozzi I, Camillo F (2007) One year old fillies can be successfully used as embryo donors. Theriogenology 67:367–371CrossRefPubMedGoogle Scholar
  73. Panzani D, Rota A, Marmorini P, Vannozzi I, Camillo F (2014) Retrospective study of factors affecting multiple ovulations, embryo recovery, quality, and diameter in a commercial equine embryo transfer program. Theriogenology 82:807–814CrossRefPubMedGoogle Scholar
  74. Peugnet P, Wimel L, Duchamp G, Sandersen C, Camous S, Guillaume D, Dahirel M, Dubois C, Jouneau L, Reigner F, Berthelot V, Chaffaux S, Tarrade A, Serteyn D, Chavatte Palmer P (2014) Enhanced or reduced fetal growth induced by embryo transfer into smaller or larger breeds alters post-natal growth and metabolism in pre-weaning horses. PLoS One 9:e102044CrossRefPubMedPubMedCentralGoogle Scholar
  75. Pinto MR, Miragaya MH, Burns P, Douglas R, Neild DM (2017) Strategies for increasing reproductive efficiency in a commercial embryo transfer program with high performance donor mares under training. J Equine Vet Sci 54:93–97CrossRefGoogle Scholar
  76. Ricketts SW, Alonso S (1991) The effect of age and parity on the development of equine chronic endometrial disease. Equine Vet J 23:189–192CrossRefPubMedGoogle Scholar
  77. Riera F, Roldan J, Hinrichs K (2006) Patterns of embryo recovery in mares with unilateral and bilateral double ovulations. Anim Reprod Sci 94:398–399CrossRefGoogle Scholar
  78. Rocha Filho AN, Pessoa MA, Gioso MM, Alvarenga MA (2004) Transfer of equine embryos into anovulatory recipients supplemented with short or long-acting progesterone. Anim Reprod Sci 1:91–95Google Scholar
  79. Sanchez R, Blanco M, Weiss J, Rosati I, Herrera C, Bollwein H, Burger D, Sieme H (2017) Influence of embryonic size and manipulation on pregnancy rates of mares after transfer of cryopreserved equine embryos. J Equine Vet Sci 49:54–59CrossRefGoogle Scholar
  80. Skidmore JA, Boyle MS, Allen WR (1991) A comparison of two different methods of freezing horse embryos. J Reprod Fertil Suppl 44:714–716Google Scholar
  81. Slade NP, Takeda T, Squires EL, Elsden RP, Seidel GE Jr (1985) A new procedure for the cryopreservation of equine embryos. Theriogenology 24:45–58CrossRefPubMedGoogle Scholar
  82. Smith RL, Vernon KL, Kelley DE, Gibbons JR, Mortensen CJ (2012) Impact of moderate exercise on ovarian blood flow and early embryonic outcomes in mares. J Anim Sci 90:3770–3777CrossRefPubMedGoogle Scholar
  83. Squires EL, McCue PM (2007) Superovulation in mares. Anim Reprod Sci 99:1–8CrossRefPubMedGoogle Scholar
  84. Squires EL, Garcia RH, Ginther OJ (1985) Factors affecting the success of equine embryo transfer. Equine Vet J Suppl 3:920–925Google Scholar
  85. Squires EL, Mckinnon AO, Carnevale EM, Morris R, Nett TM (1987) Reproductive characteristics of spontaneous single and double ovulating mares and superovulated mares. J Reprod Fertil Suppl 35:399–403PubMedGoogle Scholar
  86. Squires EL, McCue PM, Vanderwall D (1999) The current status of equine embryo transfer. Theriogenology 51:91–104CrossRefPubMedGoogle Scholar
  87. Squires EL, Carnevale EM, McCue PM, Bruemmer JE (2003) Embryo technologies in the horse. Theriogenology 59:151–170CrossRefPubMedGoogle Scholar
  88. Stout TAE (2003) Selection and management of the embryo transfer donor mare. Pferdeheilkunde 19:685–688Google Scholar
  89. Stout TA, Meadows S, Allen WR (2005) Stage-specific formation of the equine blastocyst capsule is instrumental to hatching and to embryonic survival in vivo. Anim Reprod Sci 87:269–281CrossRefPubMedGoogle Scholar
  90. Tharasanit T, Colenbrander B, Stout TA (2005) Effect of cryopreservation on the cellular integrity of equine embryos. Reproduction 129:789–798CrossRefPubMedGoogle Scholar
  91. Vogelsang SG, Vogelsang MM (1989) Influence of donor parity and age on the success of commercial equine embryo transfer. Equine Vet J 21:71–72CrossRefGoogle Scholar
  92. Wilsher S, Allen WR (2004) An improved method for nonsurgical embryo transfer in the mare. Equine Vet Educ 16:39–44CrossRefGoogle Scholar
  93. Yanamoto Y, Oguri N, Tsutsumi Y (1982) Experiments in the freezing and storage of equine embryos. J Reprod Fertil Suppl 32:399–403Google Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • H. Sieme
    • 1
    Email author
  • J. Rau
    • 1
  • D. Tiedemann
    • 1
  • H. Oldenhof
    • 1
  • L. Barros
    • 1
  • R. Sanchez
    • 1
    • 2
  • M. Blanco
    • 1
    • 2
  • G. Martinsson
    • 3
  • C. Herrera
    • 4
  • D. Burger
    • 5
  1. 1.Unit for Reproductive Medicine—Clinic for HorsesUniversity of Veterinary Medicine HannoverHannoverGermany
  2. 2.PS PferdehaltungNeustadt-GleweGermany
  3. 3.National Stud Lower SaxonyCelleGermany
  4. 4.Clinic for Reproductive Medicine, Vetsuisse FacultyUniversity of ZürichZürichSwitzerland
  5. 5.Swiss Institute of Equine Medicine ISMEUniversity of Berne and AgroscopeAvenchesSwitzerland

Personalised recommendations