Animal Reproduction (AR)
Animal Reproduction (AR)
Original Article

Effect of hCG application at different moments of the estrous cycle on corpus luteum and uterine vascularization and serum progesterone concentration in mares

Maria Augusta Alonso, Luciano Andrade Silva, Fernanda Jordão Affonso, Kleber Menegon Lemes, Eneiva Carla Carvalho Celeghini, Renata Lançoni, Henrique Fulanetti Carvalho, Rubens Paes de Arruda

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Establishment of pregnancy after embryo transfer is the ultimate goal of an embryo transfer program and increasing pregnancy rates and reducing pregnancy loss are mandatory. The utilization of treatments to improve conception rates in recipient mares has been the focus of several research groups over the last years and the results are controversial. Some studies using human chorionic gonadotrophin (hCG) found promising results. Our hypothesis was that hCG administration would cause an additional stimulation on luteal function, uterine and luteal vascularization and progesterone concentration, and the mares would have increased uterine and cervix tone. Therefore, in the present study the effects of hCG administration to induce ovulation, on day 0 (day of ovulation) or day 5 postovulation were evaluated on corpus luteum characteristics, reproductive tract vascularization, and serum progesterone concentration from ovulation until day 15 postovulation. Groups were: G1: (control) - no hCG; G2: 2500 IU of hCG to induce ovulation when a follicle greater than 35mm and uterine edema were detected; G3: 2500 IU hCG on day 0; G4: 2500 IU hCG on day 5 postovulation. Twelve mares were randomly assigned to each group, during consecutive cycles, in a Latin Square experimental design, in a total of 48 cycles. Doppler ultrasound evaluations were performed daily from day 0 until day 15 postovulation, including mesometrial vascularity, endometrial vascularity and corpus luteum vascularity. Blood samples were collected for serum progesterone concentration. Data was analyzed using the Proc Glimmix SAS Procedure for nonparametric variables and Proc Mixed for parametric parameters. There was no treatment effect for all variables studied (P > 0.05). Characteristics were only affected by day (P < 0.05). It can be concluded that hCG administration at the time points suggested in the current study did not alter the characteristics evaluated.


Color Doppler ultrasonography, equine, horse, embryo transfer.


Allen WR. Luteal deficiency and embryo mortality in the mare. 2001. Reprod Domest Anim, 36(3-4):121-131.

Arruda RA, Visintin JA, Fleury JJ, Garcia AR, Madureira EH, Celeghini ECC, Neves Neto, JR. 2001. Existem relações entre tamanho e morfoecogenicidade do corpo lúteo detectados pelo ultra-som e os teores de progesterona plasmática em receptoras de embriões eqüinos? Braz J Vet Anim Sci, 38(5):233-239.

Beindorff N, Honnens A, Penno Y, Paul V, Bollwein H. 2009. Effects of human chorionic gonadotropin on luteal blood flow and progesterone secretion in cows and in vitro – microdialyzed corpora lutea. Theriogenology, 72:528-534.

Bergfelt DR, Adams GP. 2007. Ovulation and corpus luteum development. In: Samper J, Pycock J, McKinnon AO. Current therapy in equine reproduction.1. ed. [S.l.]: Saunders. pp.1-13.

Biermann J, Klewita J, Otzen H, Martinsson G, Burger D, Meinecke-Tillman S, Sieme H. 2014. The

effect of hCG, administered in diestrus, on luteal, ovarian and uterine blood flow, peripheral progesterone levels and pregnancy rates in mares. J Equine Vet Sci, 34:166.

Bollwein H, Maierl J, Mayer R, Stolla R. 1998. Transrectal Color Doppler sonography of the A. uterina in cyclic mares. Theriogenology, 49:1483-1488.

Bollwein H, Mayer R, Weber F, Stolla R. 2002. Luteal blood flow during the estrous cycle in mares. Theriogenology, 65: 2043-2051.

Bonafos LD, Carnevale EM, Smith CA, Ginther OJ. 1994. Development of uterine tone in nonbred and pregnant mares. Theriogenology, 42:1247-1255.

Campanile G, Vecchio D, Di Palo R, Neglia G, Gasparrini B, Prandi A, Zicarelli L, DOcchio MJ. 2008. Delayed treatment with GnRH agonist, hCG and progesterone and reduced embryonic mortality in buffaloes. Theriogenology, 70:1544-1549.

Carnevale, E.M.; Ramirez, R.J.; Squires, EL.L.; Alvarenga, M.A.; Vanderwall, D.K.; McCue, P.M. 2000. Factors affecting pregnancy rate and early embryonic death afeter equine embryo transfer. Theriogenology, 54:965-979.

Deluca CA, McCue PM, Patten ML, Squires EL. 2011. Effect of a nonsurgical embryo transfer procedure and/or altrenogest therapy on endogenous progesterone concentration in mares. J Equine Vet Sci, 37:51-62.

Evans MJ, Irvine CHG. 1976. Measurement of equine follicle stimulating hormone and luteinizing hormone: Response of anestrous mares to gonadotropin releasing hormone. Biol Reprod, 15:477-484.

Ferreira JC, Gastal EL, Ginther OJ. 2008. Uterine blood flow and perfusion in mares with uterine cysts: effect of the size of the cystic area and age. Reproduction, 135:541-550.

Fleury PDC, Alonso MA, Souza FAC, Andrade AFC, Arruda RP. 2007. Uso da gonadotrofina corionica humana (hCG) visando melhorar as características reprodutivas e fertilidade de receptoras de embriões eqüinos. Rev Bras Reprod Anim, 31(1):27-31.

Ghinea N, Vu Hai MT, Groyer-Picard MT, Houllier A, Schoevaert D, Milgrom E. 1992. Pathways of internalization of the hCG/LH receptor: immunoelectron microscopic studies in Leydig cells and transfected L-cells. J Cell Biol, 118:1347-1358.

Ginther OJ.1992. Characteristics of the ovulatory season. 1992a. In: Ginther, O.J. Reproductive biology of the mare: basic and applied aspects. 2.ed. CrossPlains, WI, USA: Equiservices publishing, 135-172.

Ginther OJ.1992b. Anovulatory season. 1992. In: Ginther, O.J. Reproductive biology of the mare: basic and applied aspects. 2.ed. CrossPlains, WI, USA: Equiservices publishing, 173-232.

Ginther OJ, Utt MD. 2004. Doppler ultrasound in equine reproduction: principles, techniques, and potential. J Equine Vet Sci, 24 (12):516-526.

Ginther OJ. 2007. Ultrasonic Imaging and Animal Reproduction: Color-Doppler Ultrasonography. Book 4. Cross Plains (WI): Equiservices Publishing, 258pp.

Ginther OJ, Gastal EL, Gastal MO, Utt MD, Beg MA. 2007. Luteal blood flow and progesterone production in mares. Anim Reprod Sci, 99:213-220.

Hansel W, Blair RM. 1996. Bovine corpus luteum: a historic overview and implications for future research. Theriogenology, 45:1267-1294.

Hartman DL. Embryo transfer. 2011. In: McKinnon AO, Squires EL, Vaala WE, Varner DD. Equine Reproduction. 2.ed. [S.l.], 2871-2879.

Hayes KEN, Ginther OJ. 1986. Role of progesterone and estrogen in development of uterine tone in mares. Theriogenology, 25(4):581-590.

Hendriks WK, Colenbrander B, Stout TAE. 2006. Effect of administering PGF 2α or hCG on day 7 after ovulation on ovarian, uterine and luteal blood flow in the mare. Anim Reprod Sci, 94:223-225.

Henneke DR, Potter GD, Kreider JL, Yeates BF. 1983. Relationship between condition score, physical measurement, and body fat percentage in mares. Equine Vet J, 15:371-372.

Hermsteiner M, Zoltan DR, Doetsch J, Rascher W, Kuenzel, W. 1999. Human chorionic gonadotropin dilates uterine and mesenteric resistance arteries in pregnant and nonpregnant rats. Pflugers Archive, 439:186-194.

Ignácio FS, Canesin HS, Pantoja JCF, Romano RM, Novaes Filho LF, Ferreira JC, Meira C. 2012. Uterine hemodynamic evaluation of the beginning of diestrous in mares. J Equine Vet Sci, 32(7):406-407.

Ishak GM, Bashir ST, Gastal MO, Gastal EL. 2017. Pre-ovulatory follicle affects corpus luteum diameter, blood flow, and progesterone production in mares. Anim Reprod Sci, 187:1-12.

Jauniaux E, Jurkovic D, Delogne-Desnoek J, Meuris, S. 1992. Influence of human chorionic gonadotrophin, oestradiol and progesterone on uteroplacental and corpus luteum blood flow in normal early pregnancy. Hum Reprod, 7:1467-1473.

Kelly CM, Hoyer PB, Wise ME. 1988. In-vitro and in-vivo responsiveness of the corpus luteum of the mare to gonadotrophin stimulation. J Reprod Fertil, 84:593-600.

Khan T, Hastie PM, Beck NFG, Khalid M. 2003. hCG treatment on day of mating improves embryo viability and fertility in ewe lambs. Anim Reprod Sci, 76(Suppl.1):81-89.

King SS. Autumnal transition out of the breeding season. 2011. In: McKinnon AO, Squires EL, Vaala WE, Varner DD. Equine Reproduction. 2.ed. [S.l.], 1732-1753.

Koblischke P, Kindahl H, Budik S, Aurich J, Palmd F, Walter I, Kolodziejek J, Nowotny N, Hoppen H-O, 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, 70:1147-58.

Koblischke P, Budik S, Muller J, Aurich C. 2010. Practical experience with the treatment of recipient mares with a non-steroidal anti-inflammatory drug in an equine embryo transfer programme. Reprod Domest Anim, 45:1039-1041.

Kohne M, Kuhl J, Ille N, Erber R, Aurich C. 2014. Treatment with human chorionic gonadotrophin before ovulation increases progestin concentration in early equine pregnancies. Anim Reprod Sci, 149(3-4):187-193.

Lopes EP, Siqueira JB, Pinho RO, Guimarães JD,

Rocha AN, Carvalho GR, Torres CAA. 2011. Reproductive parameters in Mangalarga Marchador mares in a commercial embryo transfer programme. Reprod Domest Anim, 46: 261-267.

McCue PM, Vanderwall DK, Keith SL, Squires EL. 1999. Equine embryo transfer: influence of endogenous progesterone concentration in recipients on pregnancy outcome, Theriogenology, 51(1):267. (Abstract).

Nephew KP, Cardenas H, Mcclure KE, Ott TL, Bazer FW, Pope WF. 1994. Effects of administration of human chorionic gonadotrophin or progesterona befores maternal recognition of pregnancy on blastocyst development and pregnancy in sheep. J Anim Sci, 72:453-458.

Pelehach LM, Greaves HE, Porter MB, Desvousges A, Sharp DC. 2002. The role of estrogen and progesterone in the induction and dissipation of uterine edema in mares. Theriogenology, 58:441-444.

Rao CV, Alsip NL. 2001. Use of the rat model to study hCG/LH effects on uterine blood flow. Semin Reprod Med, 19:75-85.

Rizos D, Scully S, Kelly AK, Ealy AD, Moros R, Duffy P; Nain AA, Forde N, Lonergan P. 2012. Effects of human chorionic gonadotrophin administration on day 5 after oestrous on corpus luteum characteristics, circulating progesterone and conceptus elongation in cattle. Reprod Fertil Dev, 24:472-481.

Saharrea A, Valencia J, Balcázar A, Mejía O, Cerbón JL, Caballero V, Zarco L. 1998. Premature luteal regression in goats superovulated with PMSG: effect of hCG or GnRH administration during the early luteal phase. Theriogenology, 50:1039-1052.

Santos JE, Thatcher WW, Pool L, Overton MW. 2001. Effect of human chorionic gonadotropin on luteal function and reproductive performance of high-producing lactating Holstein dairy cows. Jl Anim Sci, 79: 2881-2894.

Schmitt EJ, Barros CM, Fields PA, Fields MJ, Diaz T, Kluge JM, Thatcher, VW. 1996. A cellular and endocrine characterization of the original and induced corpus luteum after administration of a gonadotropin-releasing hormone agonist or human chorionic gonadotropin on day five of the estrous cycle. J Animl Sci, 74:1915-1929.

Silva LA, Gastal EL, Beg MA, Ginther OJ. 2005. Changes in vascular perfusion of the endometrium in association with changes in location of the embryonic vesicle in mares. Biol Reprod, 72:755-761.

Silvia PJ, Squires EL, Nett TM. 1986. Changes in the hypothalamic-hypophyseal axis of mares associated with seasonal reproductive recrudescence. Biol Reprod, 35:897-905.

Tsampalas M, Grideleta V, Berndtb S, Foidart J, Geenena V, Perrier d’Hauterivea S. 2010. Human chorionic gonadotropin: A hormone with immunological and angiogenic properties. J Reprod Immunol, 85(1):93-98.

Vecchio, D, Neglia G, Di Palo R, Prandi A, Gasparrini B, Balestrieri A, D'Occhio MJ, Zicarelli L, Campanile G. 2010. Is a delayed treatment with GnRH, HCG or progesterone beneficial for reducing embryonic mortality in buffaloes? 2010. Reprod Domest Anim, 45(4):614-618.

Ziecik AJ, Stanchev PD, Tilton JE. 1986. Evidence for the presence of luteinizing hormone/human chorionic gonadotropin-binding sites in the porcine uterus. Endocrinology, 119:1159-1163.

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