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Home / Equine Research Bank / Acta Vet Scand / Recovery rate and quality of embryos from mares inseminated ...
Acta veterinaria Scandinavica1996; 37(3); 343-350; doi: 10.1186/BF03548100

Recovery rate and quality of embryos from mares inseminated at the first post-partum oestrus.

Abstract: The pregnancy rate is lower in mares inseminated at the first post-partum (p.p.) oestrus (40-50%) compared with pregnancy rates in subsequent oestrous cycles (55-65%). The causes of the lowered pregnancy rate are not fully understood. The aim of the present study was to examine if embryonic defects could be one of the reasons for lowered pregnancy rate. A total of 23 p.p. and 14 non-lactating control mares were flushed 7 days after detection of ovulation. Embryo recovery rate was 48% and 71% in p.p. and control mares, respectively (p = 0.16). Embryos were photographed, measured, graded and stained with fluorescein diacetate to assess their viability. Thereafter embryos were bisected and stained with Hoechst 33342 to count the cell nuclei. Embryos in both groups were equally viable and the cell numbers were not significantly different. According to morphological evaluation all embryos were classified as excellent or good. Embryos aged 7.3 to 7.6 days (+/-0.25 days) were smaller in the p.p. group than in the control group (p 0.10). Recovery of embryos was not related to histological findings in uterine biopsies taken after embryo recovery. Embryo recovery rate in p.p. mares (48%) was similar to previously reported foal heat pregnancy rates (40-50%). Hence, early embryonic death in utero would not be the most likely reason for lowered pregnancy rate in mares inseminated at the first p.p. oestrus. Sperm transport and oviductal conditions by the time of the first p.p. oestrus would need to be studied to clarify the role of fertilisation failure as the cause of lower pregnancy rate in mares inseminated at foal heat. Dräktighetsprocenten är lägre hos ston inseminerade i den första post-partum brunsten. Embryourspolning användes för att utreda om defekter i embryon var en av orsakerna till lägre dräktighetsprocent. Embryon från 23 post-partum och 14 icke-lakterande kontrolllston urspolades 7 dagar efter en uppskattad ovulation. Frekvensen funna embryon var 11/23 (48%) och 10/14 (71%) hos post-partum respektive kontrollston. Skillnaden var inte statistiskt signifikant (p = 0,16). Embryona färgades med fluorescein diacetat för att bedömma deras vitalitet, och med Hoechst 33342 för att räkna antalet cellkärnor. Embryona i de båda grupperna uppvisade samma vitalitet och deras cellantal var inte signifikant olika. Storleken hos 7,3 till 7,6 dagar (± 0,25 dagar) gamla embryon var mindre i post-partum gruppen än i kontroll gruppen. Orsaken till att fölbrunst embryona var mindre, kan vara en 2,4 timmars skillnad i tidsintervall från ovulationen till embryourspolningen. Frekvensen funna embryon motsvarade tidigare rapporterad dräktighetsprocenten i den första postpartum brunsten. Därför är en tidig embryodöd i livmodern inte den mest troliga orsaken till den lägre dräktighetsprocenten hos ston inseminerade i den första post-partum brunsten. Spermatransporten och äggledarens kondition under den första post-partum brunsten kräver mera forskning i framtiden.
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Publication Date: 1996-01-01 PubMed ID: 8996879PubMed Central: PMC8063999DOI: 10.1186/BF03548100Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research examines the low pregnancy rates in mares after insemination during their first oestrous cycle post-partum, to clarify if embryonic defects could be the cause. Surprisingly, despite the lower fertilisation rates, the research findings showed that the embryos from these mares were viable and of good to excellent quality, indicating other factors like sperm transport and oviductal conditions may be responsible for the lower pregnancy rates.

Research Approach

  • The researchers studied a group of 23 mares that had just given birth (post-partum) and 14 non-lactating control mares.
  • They initiated the research phase after detection of ovulation and flushed the mares seven days later.
  • The embryo recovery rate was 48% in post-partum mares and 71% in control mares.

Embryo Evaluation

  • The recovered embryos were assessed for their viability using a fluorescein diacetate stain which shows the physiology of living cells.
  • The embryos were also bisected and stained with Hoechst 33342 to count the cell nuclei, which gives an idea about the growth and development of the embryos.

Findings

  • The embryos from both groups showed equal viability according to the physiological and morphological evaluations.
  • The research showed that the embryos aged 7.3 to 7.6 days from the post-partum group were smaller than those in the control group, but it was not considered significant enough to impact the pregnancy rates.
  • The presence of bacteria and neutrophils in the uterine swabs, albeit at higher levels in the post-partum group, were not found to have a significant impact on the embryo recovery rate.

Implications and Future Research

  • Although the percentage of embryos recovered was similar to the reported foal heat pregnancy rates, early in utero embryonic death does not appear to be the primary reason for lowered pregnancy rates in mares inseminated at the first post-partum oestrus.
  • The research provides a shift in perspective towards other factors like sperm transport and oviductal conditions at the time of the first post-partum oestrus as possible causes of reduced pregnancy rates.
  • Thus, future research should aim to investigate these areas to get more insights into the lower pregnancy rates observed in mares after their first oestrous cycle post-partum.

Cite This Article

APA
Huhtinen M, Reilas T, Katila T. (1996). Recovery rate and quality of embryos from mares inseminated at the first post-partum oestrus. Acta Vet Scand, 37(3), 343-350. https://doi.org/10.1186/BF03548100

Publication

Acta veterinaria Scandinavica
ISSN: 0044-605X
NlmUniqueID: 0370400
Country: England
Language: English
Volume: 37
Issue: 3
Pages: 343-350

Researcher Affiliations

Huhtinen, M
  • Agricultural Research Centre, Ypäjä, Finland. mirja.huhtinen@mtt.fi
Reilas, T
    Katila, T

      MeSH Terms

      • Animals
      • Bacteria / isolation & purification
      • Embryo, Mammalian / cytology
      • Embryo, Mammalian / physiology
      • Estrus
      • Female
      • Horses
      • Insemination
      • Male
      • Neutrophils / cytology
      • Postpartum Period
      • Pregnancy
      • Pregnancy, Animal
      • Uterus / microbiology
      • Uterus / physiology

      References

      This article includes 43 references
      1. Andrews FN, McKenzie FF. Estrus, ovulation and related phenomena in the mare.. Res. Bull. 329, Univ. Missouri-Columbia, 1941.
      2. Badi AM, O 'Byrne TM, Cunningham EP. An analysis of reproductive performance in Thoroughbred mares.. Ir. Vet. J. 1981;35:1–12.
      3. Bain AM. Foetal losses during pregnancy in the thoroughbred mare: a record of 2,562 pregnancies.. N Z Vet J 1969 Aug;17(8):155-8.
        doi: 10.1080/00480169.1969.33811pubmed: 5260644google scholar: lookup
      4. Ball BA, Little TV, Hillman RB, Woods GL. Pregnancy rates at Days 2 and 14 and estimated embryonic loss rates prior to day 14 in normal and subfertile mares.. Theriogenology 1986 Nov;26(5):611-9.
        doi: 10.1016/0093-691X(86)90168-8pubmed: 16726227google scholar: lookup
      5. Ball BA, Little TV, Weber JA, Woods GL. Survival of day-4 embryos from young, normal mares and aged, subfertile mares after transfer to normal recipient mares.. J Reprod Fertil 1989 Jan;85(1):187-94.
        doi: 10.1530/jrf.0.0850187pubmed: 2915352google scholar: lookup
      6. Blanchard TL, Varner DD, Brinsko SP, Quirk K, Rugila JN, Boehnke L. Effects of ecbolic agents on measurements of uterine involution in the mare.. Theriogenology 1991 Oct;36(4):559-71.
        doi: 10.1016/0093-691X(91)90395-Tpubmed: 16727027google scholar: lookup
      7. Caslick EA. The sexual cycle and its relation to ovulation with breeding records of the Thoroughbred mare.. Cornell Vet. 1937;27:187–206.
      8. Gygax AP, Ganjam VK, Kenney RM. Clinical, microbiological and histological changes associated with uterine involution in the mare.. J Reprod Fertil Suppl 1979;(27):571-8.
        pubmed: 289838
      9. Douglas RH. Some aspects of equine embryo transfer.. J Reprod Fertil Suppl 1982;32:405-8.
        pubmed: 6962874
      10. Fischer B, Beier HM. Uterine environment in early pregnancy.. In: Sreenan JM, Diskin MG, editors. Embryonic mortality in farm animals. Dordrecht, Netherlands: Martinus Nijhoff Publishers; 1986. pp. 93–108.
      11. Griffin PG, Ginther OJ. Uterine morphology and function in postpartum mares.. Equine Vet. Sci. 1991;77:330–339.
        doi: 10.1016/S0737-0806(06)81262-1google scholar: lookup
      12. Katila T, Koskinen E, Oijala M, Parviainen P. Evaluation of the post-partum mare in relation to foal heat breeding. II. Uterine swabbing and biopsies.. Zentralbl Veterinarmed A 1988 May;35(5):331-9.
        doi: 10.1111/j.1439-0442.1988.tb00043.xpubmed: 3138845google scholar: lookup
      13. Kenney RM, Doig PA. Equine endometrial biopsy.. In: Morrow DA, editor. Current Therapy in Theriogenology. Philadelphia: W.B.Saunders Co.; 1986. pp. 723–729.
      14. Koskinen E. Post-partum ovarian activity in Finnhorse mares with special reference to seasonal effects.. Acta Vet Scand 1991;32(3):313-8.
        doi: 10.1186/BF03546960pmc: PMC8127901pubmed: 1814180google scholar: lookup
      15. Koskinen E, Kurki E, Katila T. Onset of luteal activity in foaling and seasonally anoestrous mares treated with artificial light.. Acta Vet Scand 1991;32(3):307-12.
        doi: 10.1186/BF03546959pmc: PMC8127909pubmed: 1814179google scholar: lookup
      16. LeBlanc MM, Hansen PJ, Buhi WC. Uterine protein secretion in postpartum and cyclic mares.. Theriogenology 1988;29:1303–1316.
        doi: 10.1016/0093-691X(88)90010-6google scholar: lookup
      17. Lieux P. Comparative results of breeding on first and second post-foaling heat periods. Proc. 26th Annu. Conv. Amer. Assoc. Equine. Pract. 1980; pp. 129–132.
      18. Lowis TC, Hyland JH. Analysis of post-partum fertility in mares on a thoroughbred stud in southern Victoria.. Aust Vet J 1991 Sep;68(9):304-6.
        doi: 10.1111/j.1751-0813.1991.tb03265.xpubmed: 1953565google scholar: lookup
      19. Loy RG. Characteristics of postpartum reproduction in mares.. Vet Clin North Am Large Anim Pract 1980 Nov;2(2):345-9.
        doi: 10.1016/S0196-9846(17)30167-2pubmed: 7233773google scholar: lookup
      20. Loy RG. The arithmetic of postpartum breeding decision in mares. Proc. Annu. Meet. Soc. Therioge-nol. 1988; pp. 13–18.
      21. McKinnon AO, Squires EL. Morphologic assessment of the equine embryo.. J Am Vet Med Assoc 1988 Feb 1;192(3):401-6.
        pubmed: 3281922
      22. McKinnon AO, Squires EL, Harrison LA, Blach EL, Shideler RK. Ultrasonographic studies on the reproductive tract of mares after parturition: effect of involution and uterine fluid on pregnancy rates in mares with normal and delayed first postpartum ovulatory cycles.. J Am Vet Med Assoc 1988 Feb 1;192(3):350-3.
        pubmed: 3281921
      23. von Merkt H. Fohlenrosse und Fruchtresorption.. Zuchthygiene 1966;7:102–108.
        doi: 10.1111/j.1439-0531.1966.tb00019.xgoogle scholar: lookup
      24. Mohr LR, Trounson AO. The use of fluorescein diacetate to assess embryo viability in the mouse.. J Reprod Fertil 1980 Jan;58(1):189-96.
        doi: 10.1530/jrf.0.0580189pubmed: 6987396google scholar: lookup
      25. Oguri N, Tsutsumi Y. Non-surgical recovery of equine eggs, and an attempt at non-surgical egg transfer in horses.. J Reprod Fertil 1972 Nov;31(2):187-95.
        doi: 10.1530/jrf.0.0310187pubmed: 4637635google scholar: lookup
      26. Pascoe DR, Liu IKM, Spensley MS, Hughes JP. Effect of endometrial pathology on the success of non-surgical embryo transfer.. Equine Vet. J. 1985; pp. 108–110.
      27. Platt H. Aetiological aspects of abortion in the thoroughbred mare.. J Comp Pathol 1973 Apr;83(2):199-205.
        doi: 10.1016/0021-9975(73)90043-1pubmed: 4796892google scholar: lookup
      28. Pruitt JA, Wilson JM, Kraemer DC. Viability of equine embryos following fluorescein diacetate staining.. Theriogenology 1988;29:291.
        doi: 10.1016/0093-691X(88)90119-7google scholar: lookup
      29. Pruitt JA, Forrest DW, Burghardt RC, Evans JW, Kraemer DC. Viability and ultrastructure of equine embryos following culture in a static or dynamic system.. J Reprod Fertil Suppl 1991;44:405-10.
        pubmed: 1795284
      30. Purswell BJ, Ley WB, Sriranganathan N, Bowen JM. Aerobic and anaerobic bacterial flora in the postpartum mare.. Equine, vet. Sci. 1989;9:141–144.
        doi: 10.1016/S0737-0806(89)80020-6google scholar: lookup
      31. Saltiel A, Gutierrez A, de Buen-Llado N, Sosa C. Cervico-endometrial cytology and physiological aspects of the post-partum mare.. J Reprod Fertil Suppl 1987;35:305-9.
        pubmed: 3479585
      32. SAS Institute Inc.. SAS/STAT™ User's Guide, Release 6.03 Edition.. Cary, NC: SAS Institute, Inc., 1988, 1028 pp..
      33. Scherbarth R. [On the occurrence of embryonic resorption by mares in the Hanoverian Warm Blood breed (author's transl)].. Dtsch Tierarztl Wochenschr 1980 May 5;87(5):189-91.
        pubmed: 6995082
      34. Schilling E, Smidt D, Sacher B, Petac D, El Kaschab S. Diagnosis of the viability of early bovine embryos by fluorescence microscopy.. Ann. Biol. Anim. Biochim. Biophys. 1979;19:1625–1629.
        doi: 10.1051/rnd:19790924google scholar: lookup
      35. Squires EL, Imel KJ, Iuliano MF, Shideler RK. Factors affecting reproductive efficiency in an equine embryo transfer programme.. J Reprod Fertil Suppl 1982;32:409-14.
        pubmed: 6962875
      36. Squires EL, Barnes CK, Rowley HS, McKinnon AO, Pickett BW, Shideler RK. Effect of uterine fluid and volume of extender on fertility. Proc. 35th Annu. Conv. Amer. Assoc. Equine Pract. 1989; pp. 25–30.
      37. Sullivan JJ, Turner PC, Self LC, Gutteridge HB, Bartlett DE. Survey of reproductive efficiency in the Quarter-horse and Thoroughbred.. J Reprod Fertil Suppl 1975 Oct;(23):315-8.
        pubmed: 1060797
      38. Torp M, Helmen P, Odegaard S. Early pregnancy loss in the mare, loss rates and etiological aspects.. Norsk. Vet.Tidsskr. 1989;101:319–327.
      39. van Niekerk CH, Gerneke WH. Persistence and parthenogentic cleavage of tubal ova in the mare.. Onderstepoort J Vet Res 1966 Jun;33(1):195-232.
        pubmed: 6007779
      40. Wilson JM, Kreider JL, Potter GD, Kraemer DC. Nonsurgical recovery of degenerative ova from the uteri of mares.. Theriogenology 1991 Oct;36(4):629-36.
        doi: 10.1016/0093-691X(91)90400-8pubmed: 16727032google scholar: lookup
      41. Woods GL, Baker CB, Hulman RB, Schlafer DH. Recent studies relating to early embryonic death in the mare.. Equine vet. J. 1985;3:104–107.
      42. Woods GL, Hillman RB, Schlafer DH. Recovery and evaluation of embryos from normal and infertile mares.. Cornell Vet 1986 Oct;76(4):386-94.
        pubmed: 3757521
      43. Woods GL, Baker CB, Baldwin JL, Ball BA, Bilinski J, Cooper WL, Ley WB, Mank EC, Erb HN. Early pregnancy loss in brood mares.. J Reprod Fertil Suppl 1987;35:455-9.
        pubmed: 3479600

      Citations

      This article has been cited 1 times.
      1. Cardona-García M, Jiménez-Escobar C, Ferrer MS, Maldonado-Estrada JG. Follicular Dynamics and Pregnancy Rates during Foal Heat in Colombian Paso Fino Mares Bred under Permanent Grazing. Animals (Basel) 2024 Feb 29;14(5).
        doi: 10.3390/ani14050760pubmed: 38473144google scholar: lookup
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