Effects of human chorionic gonadotrophin administration on Day 5 after oestrus on corpus luteum characteristics, circulating progesterone and conceptus elongation in cattle
D. Rizos A , S. Scully B , A. K. Kelly B , A. D. Ealy C , R. Moros A , P. Duffy B , A. Al Naib B , N. Forde B and P. Lonergan B D
+ Author Affiliations
- Author Affiliations
A Departamento de Reproducción Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de la Coruna, KM 5.9, 28040 Madrid, Spain.
B School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland.
C Department of Animal Sciences, University of Florida, PO Box 110910, Gainesville, FL 32611-0910, USA.
D Corresponding author. Email: pat.lonergan@ucd.ie
Reproduction, Fertility and Development 24(3) 472-481 https://doi.org/10.1071/RD11139
Abstract
The aim of the present study was to test the hypothesis that elevated concentrations of progesterone (P4) resulting from the induction of an accessory corpus luteum (CL) by human chorionic gonadotrophin (hCG) administration on Day 5 after oestrus would lead to advanced conceptus elongation on Day 14 following embryo transfer on Day 7. The oestrous cycles of cross-bred beef heifers were synchronised and animals were randomly assigned to receive either of two treatments: (1) intramuscular injection of 3000 IU hCG on Day 5 after oestrus (n = 14); or (2) intramuscular injection of saline on Day 5 after oestrus (n = 13). Ovaries were scanned daily by transrectal ultrasonography to assess CL development. Serum concentrations of P4 were determined from daily blood samples collected from the jugular vein. In vitro-produced bovine blastocysts were transferred to synchronised recipients on Day 7 after oestrus (n = 15 blastocysts per recipient). Heifers were killed on Day 14 after oestrus and the uterus was flushed to recover the embryos. Injection of hCG on Day 5 induced ovulation of the dominant follicle in all treated heifers and increased the total area of luteal tissue on the ovary, which was associated with a significant increase (P < 0.001) in serum concentrations of P4 from Day 7 to Day 14. Positive associations were detected between circulating P4 with CL area (within-day correlations ranging from r = 0.45 to r = 0.67) and total area of luteal tissue (within-day correlations ranging from r = 0.65 to r = 0.86) Administration of hCG did not affect the proportion of Day 14 conceptuses recovered. However, compared with the control group, hCG-treated heifers had increased conceptus length (3.91 ± 1.23 vs 5.57 ± 1.02 mm, respectively; P = 0.06), width (1.00 ± 0.06 vs 1.45 ± 0.05 mm, respectively; P = 0.002) and area (5.71 ± 0.97 vs 8.31 ± 0.83, respectively; P = 0.02). Although numerically greater, mean interferon-τ (IFNT) production in vitro did not differ significantly (P = 0.54) between embryos recovered from hCG-treated and control heifers. In contrast, there was a strong positive correlation between individual embryo length (r = 0.76; P < 0.001) and individual embryo area (r = 0.72; P < 0.001) and IFNT production. In conclusion, administration of hCG on Day 5 after oestrus resulted in the formation of an accessory CL and hypertrophy of the original CL, the result of which was an increase in P4 concentrations from Day 7 onwards. These elevated P4 concentrations were associated with an increased conceptus area. Furthermore, conceptus size was highly correlated with IFNT secretion in vitro.
Additional keywords: bovine, fertility, hCG embryo.
References
Ashworth, C. J., Sales, D. I., and Wilmut, I. (1989). Evidence of an association between the survival of embryos and the periovulatory plasma progesterone concentration in the ewe. J. Reprod. Fertil. 87, 23–32.| Evidence of an association between the survival of embryos and the periovulatory plasma progesterone concentration in the ewe.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXls1Oltr4%3D&md5=7e2b8d278c9049af90304f1e38a020a7CAS | 2621699PubMed |
Bauersachs, S., Ulbrich, S. E., Gross, K., Schmidt, S. E., Meyer, H. H., Wenigerkind, H., Vermehren, M., Sinowatz, F., Blum, H., and Wolf, E. (2006). Embryo-induced transcriptome changes in bovine endometrium reveal species-specific and common molecular markers of uterine receptivity. Reproduction 132, 319–331.
| Embryo-induced transcriptome changes in bovine endometrium reveal species-specific and common molecular markers of uterine receptivity.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xpt1Wjs7s%3D&md5=33d6a11e661942e32cef6aa7017feac8CAS | 16885540PubMed |
Bazer, F. W., Spencer, T. E., Johnson, G. A., Burghardt, R. C., and Wu, G. (2009). Comparative aspects of implantation. Reproduction 138, 195–209.
| Comparative aspects of implantation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXptlemt74%3D&md5=0dddbbee57332fc3828ef890b3b5fea6CAS | 19502456PubMed |
Bazer, F. W., Wu, G., Spencer, T. E., Johnson, G. A., Burghardt, R. C., and Bayless, K. (2010). Novel pathways for implantation and establishment and maintenance of pregnancy in mammals. Mol. Hum. Reprod. 16, 135–152.
| Novel pathways for implantation and establishment and maintenance of pregnancy in mammals.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhslKru7g%3D&md5=7c40d13f24d56512263d26009bb0369fCAS | 19880575PubMed |
Binelli, M., Thatcher, W. W., Mattos, R., and Baruselli, P. S. (2001). Antiluteolytic strategies to improve fertility in cattle. Theriogenology 56, 1451–1463.
| Antiluteolytic strategies to improve fertility in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xjslyqtg%3D%3D&md5=6f643355f3fb40f691ab896b03e672d2CAS | 11768810PubMed |
Breuel, K. F., Spitzer, J. C., Thompson, C. E., and Breuel, J. F. (1990). First-service pregnancy rate in beef heifers as influenced by human chorionic gonadotropin administration before and/or after breeding. Theriogenology 34, 139–145.
| First-service pregnancy rate in beef heifers as influenced by human chorionic gonadotropin administration before and/or after breeding.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3MXisVSktbo%3D&md5=c7a4b0a411849946522b70a610ac291fCAS | 16726824PubMed |
Carter, F., Forde, N., Duffy, P., Wade, M., Fair, T., Crowe, M. A., Evans, A. C., Kenny, D. A., Roche, J. F., and Lonergan, P. (2008). Effect of increasing progesterone concentration from Day 3 of pregnancy on subsequent embryo survival and development in beef heifers. Reprod. Fertil. Dev. 20, 368–375.
| Effect of increasing progesterone concentration from Day 3 of pregnancy on subsequent embryo survival and development in beef heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXjtVKksLg%3D&md5=fb0e332b80e7323eedc60036d56ef2c8CAS | 18402756PubMed |
Chagas e Silva, J., and Lopes da Costa, L. (2005). Luteotrophic influence of early bovine embryos and the relationship between plasma progesterone concentrations and embryo survival. Theriogenology 64, 49–60.
| Luteotrophic influence of early bovine embryos and the relationship between plasma progesterone concentrations and embryo survival.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXltVGkt7c%3D&md5=53324ad378726b9322ef564b36d3e6ccCAS | 15935842PubMed |
Clemente, M., de La Fuente, J., Fair, T., Al Naib, A., Gutierrez-Adan, A., Roche, J. F., Rizos, D., and Lonergan, P. (2009). Progesterone and conceptus elongation in cattle: a direct effect on the embryo or an indirect effect via the endometrium? Reproduction 138, 507–517.
| Progesterone and conceptus elongation in cattle: a direct effect on the embryo or an indirect effect via the endometrium?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhtFOgtrvL&md5=c2b93accf694e764a9eab6c4efb1a01cCAS | 19556439PubMed |
Dahlen, C. R., Bird, S. L., Martel, C. A., Olson, K., Stevenson, J. S., and Lamb, G. C. (2010). Administration of human chorionic gonadotropin 7 days after fixed-time artificial insemination of suckled beef cows. J. Anim. Sci. 88, 2337–2345.
| Administration of human chorionic gonadotropin 7 days after fixed-time artificial insemination of suckled beef cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXos1Kmsb0%3D&md5=d026ee5a001526c3d39e9d1ead45577eCAS | 20190162PubMed |
De Rensis, F., Lopez-Gatius, F., Garcia-Ispierto, I., and Techakumpu, M. (2010). Clinical use of human chorionic gonadotropin in dairy cows: an update. Theriogenology 73, 1001–1008.
| Clinical use of human chorionic gonadotropin in dairy cows: an update.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXktlClu74%3D&md5=d6c2ba3fd70bbce7c1bfbe948c314589CAS | 20116839PubMed |
Diaz, T., Schmitt, E. J., de la Sota, R. L., Thatcher, M. J., and Thatcher, W. W. (1998). Human chorionic gonadotropin-induced alterations in ovarian follicular dynamics during the estrous cycle of heifers. J. Anim. Sci. 76, 1929–1936.
| 1:CAS:528:DyaK1cXkvV2ht7s%3D&md5=e79db44defd77e1976c055b76847684fCAS | 9690649PubMed |
Diskin, M. G., and Morris, D. G. (2008). Embryonic and early foetal losses in cattle and other ruminants. Reprod. Domest. Anim. 43(Suppl. 2), 260–267.
| Embryonic and early foetal losses in cattle and other ruminants.Crossref | GoogleScholarGoogle Scholar |
Diskin, M. G., Murphy, J. J., and Sreenan, J. M. (2006). Embryo survival in dairy cows managed under pastoral conditions. Anim. Reprod. Sci. 96, 297–311.
| Embryo survival in dairy cows managed under pastoral conditions.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD28nitFGgsg%3D%3D&md5=f621fa13f142ae2bc5883fc87ec717b6CAS | 16963203PubMed |
Farin, C. E., Moeller, C. L., Mayan, H., Gamboni, F., Sawyer, H. R., and Niswender, G. D. (1988). Effect of luteinizing hormone and human chorionic gonadotropin on cell populations in the ovine corpus luteum. Biol. Reprod. 38, 413–421.
| Effect of luteinizing hormone and human chorionic gonadotropin on cell populations in the ovine corpus luteum.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1cXhs1Wrs7w%3D&md5=56351d7f1ddf525bd7ef74c4265aa9feCAS | 3162812PubMed |
Forde, N., Carter, F., Fair, T., Crowe, M. A., Evans, A. C., Spencer, T. E., Bazer, F. W., McBride, R., Boland, M. P., O’Gaora, P., Lonergan, P., and Roche, J. F. (2009). Progesterone-regulated changes in endometrial gene expression contribute to advanced conceptus development in cattle. Biol. Reprod. 81, 784–794.
| Progesterone-regulated changes in endometrial gene expression contribute to advanced conceptus development in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhtFyhsLbM&md5=d5b87f63f4bfb6dba0d5025dcdce42adCAS | 19553605PubMed |
Forde, N., Beltman, M. E., Duffy, G. B., Duffy, P., Mehta, J. P., O’Gaora, P., Roche, J. F., Lonergan, P., and Crowe, M. A. (2011). Changes in the endometrial transcriptome during the bovine estrous cycle: effect of low circulating progesterone and consequences for conceptus elongation. Biol. Reprod. 84, 266–278.
| Changes in the endometrial transcriptome during the bovine estrous cycle: effect of low circulating progesterone and consequences for conceptus elongation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhsVeltr4%3D&md5=f5452608cf2c4895d4fb4fdcc1a16252CAS | 20881316PubMed |
Funston, R. N., Lipsey, R. J., Geary, T. W., and Roberts, A. J. (2005). Effect of administration of human chorionic gonadotropin after artificial insemination on concentrations of progesterone and conception rates in beef heifers. J. Anim. Sci. 83, 1403–1405.
| 1:CAS:528:DC%2BD2MXksFahsrY%3D&md5=3047cebe8455338e2381b9dcfb719076CAS | 15890818PubMed |
Galvão, K. N., Santos, J. E., Coscioni, A. C., Juchem, S. O., Chebel, R. C., Sischo, W. M., and Villaseñor, M. (2006). Embryo survival from gossypol-fed heifers after transfer to lactating cows treated with human chorionic gonadotropin. J. Dairy Sci. 89, 2056–2064.
| Embryo survival from gossypol-fed heifers after transfer to lactating cows treated with human chorionic gonadotropin.Crossref | GoogleScholarGoogle Scholar | 16702269PubMed |
Garrett, J. E., Geisert, R. D., Zavy, M. T., and Morgan, G. L. (1988). Evidence for maternal regulation of early conceptus growth and development in beef cattle. J. Reprod. Fertil. 84, 437–446.
| Evidence for maternal regulation of early conceptus growth and development in beef cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXhtFKh&md5=200238746a458a126cfa3b13bbd825afCAS | 3199361PubMed |
Gray, C. A., Taylor, K. M., Ramsey, W. S., Hill, J. R., Bazer, F. W., Bartol, F. F., and Spencer, T. E. (2001). Endometrial glands are required for preimplantation conceptus elongation and survival. Biol. Reprod. 64, 1608–1613.
| Endometrial glands are required for preimplantation conceptus elongation and survival.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXjvFGgsbs%3D&md5=05e8407b7cf6158126811d3aed3c6062CAS | 11369585PubMed |
Hanlon, D. W., Jarratt, G. M., Davidson, P. J., Millar, A. J., and Douglas, V. L. (2005). The effect of hCG administration five days after insemination on the first service conception rate of anestrous dairy cows. Theriogenology 63, 1938–1945.
| The effect of hCG administration five days after insemination on the first service conception rate of anestrous dairy cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXjt1Kjtb8%3D&md5=250bafe1fb655690221bf867c8421f0eCAS | 15823350PubMed |
Inskeep, E. K. (2004). Preovulatory, postovulatory, and postmaternal recognition effects of concentrations of progesterone on embryonic survival in the cow. J. Anim. Sci. 82(E-Suppl.), E24–E39.
Kerbler, T. L., Buhr, M. M., Jordan, L. T., Leslie, K. E., and Walton, J. S. (1997). Relationship between maternal plasma progesterone concentration and interferon-tau synthesis by the conceptus in cattle. Theriogenology 47, 703–714.
| Relationship between maternal plasma progesterone concentration and interferon-tau synthesis by the conceptus in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXhvFCltL8%3D&md5=99e5d7daa03d83aed943b08160ca6779CAS | 16728022PubMed |
Lamb, G. C., Dahlen, C. R., Larson, J. E., Marquezini, G., and Stevenson, J. S. (2010). Control of the estrous cycle to improve fertility for fixed-time artificial insemination in beef cattle: a review. J. Anim. Sci. 88, E181–E192.
| Control of the estrous cycle to improve fertility for fixed-time artificial insemination in beef cattle: a review.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3c3pslOgug%3D%3D&md5=ba470a4c00ecce64f13921ddff268a67CAS | 19783709PubMed |
Lonergan, P. (2011). Influence of progesterone on oocyte quality and embryo development in cows. Theriogenology, , .
| Influence of progesterone on oocyte quality and embryo development in cows.Crossref | GoogleScholarGoogle Scholar |
Mann, G. E., and Lamming, G. E. (1999). The influence of progesterone during early pregnancy in cattle. Reprod. Domest. Anim. 34, 269–274.
| The influence of progesterone during early pregnancy in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXls1Knu7Y%3D&md5=51a67d7ef6b5d80782dc71e3c657a1c3CAS |
Mann, G. E., and Lamming, G. E. (2001). Relationship between maternal endocrine environment, early embryo development and inhibition of the luteolytic mechanism in cows. Reproduction 121, 175–180.
| Relationship between maternal endocrine environment, early embryo development and inhibition of the luteolytic mechanism in cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXnslaqsw%3D%3D&md5=0cff2af4bde33565a3ea81d4f78fa305CAS | 11226041PubMed |
McNeill, R. E., Diskin, M. G., Sreenan, J. M., and Morris, D. G. (2006). Associations between milk progesterone concentration on different days and with embryo survival during the early luteal phase in dairy cows. Theriogenology 65, 1435–1441.
| Associations between milk progesterone concentration on different days and with embryo survival during the early luteal phase in dairy cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xis1Srsbs%3D&md5=9116c02b2311f640b37db58012a680f6CAS | 16207495PubMed |
Michael, D. D., Alvarez, I. M., Ocon, O. M., Powell, A. M., Talbot, N. C., Johnson, S. E., and Ealy, A. D. (2006). Fibroblast growth factor-2 is expressed by the bovine uterus and stimulates interferon-tau production in bovine trophectoderm. Endocrinology 147, 3571–3579.
| Fibroblast growth factor-2 is expressed by the bovine uterus and stimulates interferon-tau production in bovine trophectoderm.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XmtlOrsbk%3D&md5=5fad891ac70aa0aafea53d25cf95b99aCAS | 16574787PubMed |
Nephew, K. P., Cardenas, H., McClure, K. E., Ott, T. L., Bazer, F. W., and Pope, W. F. (1994). Effects of administration of human chorionic gonadotropin or progesterone before maternal recognition of pregnancy on blastocyst development and pregnancy in sheep. J. Anim. Sci. 72, 453–458.
| 1:CAS:528:DyaK2cXhvVehtr4%3D&md5=3c9a433475b54be10912179b5e6b454dCAS | 8157530PubMed |
Nishigai, M., Kamomae, H., Tanaka, T., and Kaneda, Y. (2002). Improvement of pregnancy rate in Japanese black cows by administration of hCG to recipients of transferred frozen–thawed embryos. Theriogenology 58, 1597–1606.
| Improvement of pregnancy rate in Japanese black cows by administration of hCG to recipients of transferred frozen–thawed embryos.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xms1yntrg%3D&md5=dc6866b958f77e63474a707529150d89CAS | 12374129PubMed |
Okumu, L. A., Forde, N., Fahey, A. G., Fitzpatrick, E., Roche, J. F., Crowe, M. A., and Lonergan, P. (2010). The effect of elevated progesterone and pregnancy status on mRNA expression and localisation of progesterone and oestrogen receptors in the bovine uterus. Reproduction 140, 143–153.
| The effect of elevated progesterone and pregnancy status on mRNA expression and localisation of progesterone and oestrogen receptors in the bovine uterus.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhtVWls77E&md5=6884d20c7eae26b3be6660350a8857eeCAS | 20403910PubMed |
Rizos, D., Ward, F., Duffy, P., Boland, M. P., and Lonergan, P. (2002). Consequences of bovine oocyte maturation, fertilization or early embryo development in vitro versus in vivo: implications for blastocyst yield and blastocyst quality. Mol. Reprod. Dev. 61, 234–248.
| Consequences of bovine oocyte maturation, fertilization or early embryo development in vitro versus in vivo: implications for blastocyst yield and blastocyst quality.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xlt1Giug%3D%3D&md5=16e10a964f1ea09aa433817d64549866CAS | 11803560PubMed |
Roberts, R. M., Imakawa, K., Niwano, Y., Kazemi, M., Malathy, P. V., Hansen, T. R., Glass, A. A., and Kronenberg, L. H. (1989). Interferon production by the preimplantation sheep embryo. J. Interferon Res. 9, 175–187.
| Interferon production by the preimplantation sheep embryo.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXitFSlsL8%3D&md5=1f92571544021b101e40e99b1cd035baCAS | 2469745PubMed |
Santos, J. E., Thatcher, W. W., Pool, L., and Overton, M. W. (2001). Effect of human chorionic gonadotropin on luteal function and reproductive performance of high-producing lactating Holstein dairy cows. J. Anim. Sci. 79, 2881–2894.
| 1:CAS:528:DC%2BD3MXptVaksLw%3D&md5=c328f680336f460c3811cb1e2efec3b9CAS | 11768118PubMed |
Satterfield, M. C., Bazer, F. W., and Spencer, T. E. (2006). Progesterone regulation of preimplantation conceptus growth and galectin 15 (LGALS15) in the ovine uterus. Biol. Reprod. 75, 289–296.
| Progesterone regulation of preimplantation conceptus growth and galectin 15 (LGALS15) in the ovine uterus.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XnsVWgsbo%3D&md5=30d3805fb57044ea41fe547494da71ebCAS | 16707766PubMed |
Spencer, T. E., Johnson, G. A., Bazer, F. W., Burghardt, R. C., and Palmarini, M. (2007). Pregnancy recognition and conceptus implantation in domestic ruminants: roles of progesterone, interferons and endogenous retroviruses. Reprod. Fertil. Dev. 19, 65–78.
| Pregnancy recognition and conceptus implantation in domestic ruminants: roles of progesterone, interferons and endogenous retroviruses.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xhtleitr%2FN&md5=32b9e8aa2ae697d444b5000e4137e57eCAS | 17389136PubMed |
Sreenan, J. M., and Diskin, M. G. (1986). The extent and timing of embryonic mortality in cattle. In ‘Embryonic Mortality in Farm Animals’. (Eds J. M. Sreenan and M. G. Diskin.) pp. 142–158. (Martinus Nijhoff: Brussels.)
Stevenson, J. S., Portaluppi, M. A., Tenhouse, D. E., Lloyd, A., Eborn, D. R., Kacuba, S., and DeJarnette, J. M. (2007). Interventions after artificial insemination: conception rates, pregnancy survival, and ovarian responses to gonadotropin-releasing hormone, human chorionic gonadotropin, and progesterone. J. Dairy Sci. 90, 331–340.
| Interventions after artificial insemination: conception rates, pregnancy survival, and ovarian responses to gonadotropin-releasing hormone, human chorionic gonadotropin, and progesterone.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXmsFSlsw%3D%3D&md5=62e6a4e913941031333d39e8144c3c65CAS | 17183101PubMed |
Stronge, A. J., Sreenan, J. M., Diskin, M. G., Mee, J. F., Kenny, D. A., and Morris, D. G. (2005). Post-insemination milk progesterone concentration and embryo survival in dairy cows. Theriogenology 64, 1212–1224.
| Post-insemination milk progesterone concentration and embryo survival in dairy cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXpsVCgt7o%3D&md5=143645888555a9fed755eaf0856a22edCAS | 16125563PubMed |
Wallace, L. D., Breiner, C. A., Breiner, R. A., Spell, A. R., Carter, J. A., Lamb, G. C., and Stevenson, J. S. (2011). Administration of human chorionic gonadotropin at embryo transfer induced ovulation of a first wave dominant follicle, and increased progesterone and transfer pregnancy rates. Theriogenology 75, 1506–1515.
| Administration of human chorionic gonadotropin at embryo transfer induced ovulation of a first wave dominant follicle, and increased progesterone and transfer pregnancy rates.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXkt1Kjsb8%3D&md5=6581ef6c440a69fcdff377dadd3efbb9CAS | 21295842PubMed |
