Practical aspects of equine embryo transfer
DOI:
https://doi.org/10.12775/TRVS.2019.002Keywords
Equine, embryo, donor, recipients, transfer, practitionersAbstract
This article focuses on practical aspects and most specific points of equine embryo transfer (EET). Induction of polyovylations in donor mares is not possible. Only the repetition of embryo collections can increase the number of foals from the same mares. At each oestrus, follow follicular growth and artificial inseminations are conducted in the same way as for any brood mare. It is essential to know the number and timing of ovulations at least a 12-hours accurency. Induction of ovulation is frequently required, GnRH agonists are used to do that. Embryos are flushed from the donor mare’s uterus, typically on day 7 or 8 after ovulation using a long (~1.5 m) and large (diameter 8 mm) Foley-type balloon-tipped catheter introduced by vaginal route just in front to cervix. Some practical details are important to EET practitioners, firstly, the embryos are easily located under stereo-microscope after filtration of flushing medium, and secondly most equine embryos are immediately transferred or after cooling at 4°C less than 24 hours. To have a recipient mare in the right stage of her oestrous cycle (D5 to D8 after ovulation) is the biggest and the most difficult challenge for EET practitioners because the synchronisation of oestrous and ovulations is very difficult to obtain. Therefore, embryos are transferred transcervically to the uterus of a recipient mare. Recently, a modified method using a speculum and a specific forceps seems to give a much better success rate than the conventional technique which requires a large training. The EET has regulatory constraints: regulations of different breeds allowing or not allowing the embryo transfer and sanitary European regulation concerning intra-community trade of equine embryos (Annex D to Council directive 92/65 EEC) and, in some countries, additional national regulation. The possible sanitary risks of ET in equine have been still little studied, and without International or European official registrations of EET activity, it is difficult to know the extent of the use of the technique around the world. The average success rate of embryo recovery is of the order of 40 to 50% depending on the fertility of the donor and the type of sperm used, the transfer success rate can reach 70 to 80% if the technique is well mastered by ET practitioners.References
Allen WR. Historical and modern aspects of equine embryo transfer. 25th Annual meeting of AETE, Poznan, 11th-12th September, 2009; pp: 7- 41.
McCue PM, Niswender KD, Macon KA. Modification of the flush procedure to enhance embryo recovery. J Equine Vet Sci. 2003; 23: 336 –337.
Squires EL, Carnevale EM, McCue PM, Bruemmer JE. Embryo technologies in the horse. Theriogen. 2003; 59: 151-170.
Stout, TAE. Equine embryo transfer: review of developing potential. Equine Vet J. 2006; 38: 476-478.
Hartman DL. Embryo Transfer, In "Equine Reproduction" Second edition, Ed McKinnon AO, Squires EL, Vaala WE and Varner DD, Editions Wiley-Blackwell, Ames 2011, Chapter 303, pp: 2871-2879.
McCue PM, Squires EL. Equine Embryo Transfer, Eds Teton Media, Jackson, 2015, pp: 184.
Squires EL, McCue PM. Superovulation in mares. Anim Reprod Sci. 2007; 99: 1-8.
Squires EL, McCue PM. Superovulation In "Equine Reproduction" Second edition, Ed McKinnon AO, Squires EL, Vaala WE and Varner DD, Editions Wiley-Blackwell, Ames 2011, Chapter 193, pp: 1836-1844.
Losinno L, Alonso C, Rodriguez PD, Douglas RH. Ovulation and embryo recovery rates in young and aged mares treated with hCG or deslorelin. Proceeding of 7th International Symposium on Equine Embryo transfer, Cambridge, 2008; 9-11th July, pp: 96-97.
Reira FL, Roldab JE, Hinricks K, Ipsilateral double ovulation is associated with reduced embryo recovery in mares. Proceeding of 6th International Symposium on Equine Embryo transfer, Rio de Janeiro, 4th-6th August, 2004; pp: 108-109.
Siddiqui MAR, Gastal EL, Gastal MO, Beg MA, Ginther OJ. Effect of hCG in the presence of hCG antibodies on the follicle, hormone concentrations, and the oocytes in mares. Reprod Dom Anim. 2009; 44: 474-479.
Colchen S, Battut I, Fieni F, Tainturier D, Siliart B, Bruyas JF. Quantitative histological analysis of equine embryos at exactly 156 and 168 h after ovulation. J Reprod Fertil Suppl 2000; 56:527–537.
Bruyas JF. Freezing of embryos. In "Equine Reproduction" Second edition, Ed McKinnon AO, Squires EL, Vaala WE and Varner DD, Editions Wiley-Blackwell, , Ames 2011; Chapter 305, pp: 2880-2886.
Bruyas JF, Colchen S, Grandchamp des Raux A, Nicaise JL, Battut I, Fiéni F, Tainturier D. When do horse embryos enter the uterus? Practical applications in embryo transfer. J Equine Vet Sci. 1999; 19: 582.
Moussa M, Duchamp G, Bruyas JF, Daels P. Correlation between the number of cells and the diameter of equine embryos between 6.5 and 8 days. 20th Scientific Meeting of AETE, Lyon, 10th- 11th September, 2004; 158-159.
Moussa M, Perreau C, Baril G, Duchamp G, Vidament M, Daels P, Bruyas JF, Mermillod P. Comparison of cell proliferation index in equine and caprine embryos using a modified BrdU incorporation assay. Theriogen. 2005; 64: 1823-1832.
McCue PM, DeLuca C, Wall J. Cooled transport Embryo Technology. In "Equine Reproduction" Second edition, Ed McKinnon AO, Squires EL, Vaala WE and Varner DD, Editions Wiley-Blackwell, , Ames 2011; Chapter 304, pp: 2887-2920.
Wala N, Serres C, Foss R, Arbouin C, Perez-Cabal MA, Blanco M. Effect of duration of embryo holding on recipient mares’ pregnancy rate. J Equine Vet Sci. 2018; 66: 215.
Cuervo-Arango J, Claes AN, Stout TA. Effect of embryo transfer technique on the likelihood of pregnancy in the mare: a comparison of conventional and Wilsher's forceps-assisted transfer. Vet Rec 2018; 183: 323.
Broaddus CC, Balasuriya UBR, Timoney PJ, White JLR, Makloski C, Torrisi K, Payton M, Holyoak GR. Infection of embryos following insemination of donor mares with equine arteritis virus infective semen. Theriogen. 2011; 76: 47-60.
Hébia I, Fiéni F, Duchamp G, Destrumelle S, Pellerin JL, Zientara S, Vautherot JF, Bruyas JF. Potential risk of transmission of equine herpes virus 1 (EHV1) by equine embryo transfer. Theriogen. 2007; 67: 1485-1491.
Hébia–Fellah I, Duchamp G, Larrat M, Roux C, Pellerin JL, Vautherot JF, Zientara S, Fieni F, Bruyas JF. Can equine early blastocysts (D6.5) and blastocysts (D8) previously exposed to EHV1 be decontaminated by a bath of trypsin. Proceeding of 7th Equine Embryo transfer Symposium, Cambridge, 9th-11th July, 2008; pp: 40-41.
Carvalho R, Passos LMF, Oliveira AM, Henry M, Martin AS. Detection of equine herpesvirus 1 DNA in a single embryo and in horse semen by polymerase chain reaction. Arq Bras Med Vet Zootec. 2000; 52: 302-306.
Van Soom A, Nauwynch H, Wrathall A. Scientific foundations for epidemiological safety of embryo transfer. In manual of International Embryo Transfer Society, 2011; 4th Edition, Chapter 2, pp: 13-40.
Autard de Bragard E, Bruyas JF. Retrospective survey on equine embryo transfer activities in France in 2014 and 2015. Proceeding of 34th Scientific Meeting of AETE, Nantes, 7th-8th October 2018; pp: 83.
Viana J. Statistics of embryo production and transfer in domestic farm animals. Is it a turning point ? In 2017 more in vitro produced than in vivo derived embryos were transferred worldwide. Embryo Technology Newsletter, December 2018; pp: 8-25.
Squires EL. Social acceptance of equine ARTS- USA perspective? Symposium lecture. Equine Reproduction Symposium, Paris, 9th-10th January2015.
Downloads
Published
How to Cite
Issue
Section
License
Title, logo and layout of TR in VS are reserved trademarks of TR in VR.
Stats
Number of views and downloads: 1203
Number of citations: 0