Effect of hCG administration during corpus luteum establishment on subsequent corpus luteum development and circulating progesterone concentrations in beef heifers
V. Maillo A , P. Duffy B , L. O’Hara B , C. de Frutos A , A. K. Kelly B , P. Lonergan B and D. Rizos A C
+ Author Affiliations
- Author Affiliations
A Departamento de Reproduccion Animal, Instituto Nacional de Investigacion y Tecnologıa 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 Corresponding author. Email: drizos@inia.es
Reproduction, Fertility and Development 26(3) 367-374 https://doi.org/10.1071/RD12353
Submitted: 1 November 2012 Accepted: 6 February 2013 Published: 5 March 2013
Abstract
This study examined the effect of a single administration of human chorionic gonadotrophin (hCG) on Day 1 to 4 after oestrus on corpus luteum (CL) development and circulating progesterone (P4). Oestrus-synchronized heifers (n = 43) were administered a single intramuscular injection of saline on Day 1 (control) or 3000 IU hCG on Day 1, 2, 3 or 4 after oestrus. Administration of hCG on Day 1 had no effect on CL area, on Day 2 increased CL area from Day 6 to 12 (P < 0.05), on Day 3 increased CL area from Day 9 to 11, while on Day 4 increased CL size on Days 9 and 10 (P < 0.05). Administration of hCG on Day 4 induced the formation of an accessory CL in 89% of heifers, resulting in a significant increase in total luteal tissue area on the ovaries compared with all other groups. Consistent with the effects on the CL, hCG on Day 1 did not affect P4 concentrations, on Day 2 significantly increased P4 compared with the control from Day 6 to 11 (P < 0.05), on Day 3 resulted in a non-significant increase in P4 while hCG on Day 4 increased P4 from Day 8 to 13 compared with the control (P < 0.05). In conclusion, administration of hCG as early as Day 2 after oestrus results in increased P4 in circulation from Day 6, which should have beneficial downstream effects in terms of uterine receptivity and conceptus elongation.
Additional keywords: cattle, conceptus elongation, fertility, pregnancy.
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=d87e8a95a4655ab7d599ca6a19fece8fCAS | 2621699PubMed |
Beindorff, N., Honnens, A., Penno, Y., Paul, V., and Bollwein, H. (2009). Effects of human chorionic gonadotrophin on luteal blood flow and progesterone secretion in cows and in vitro-microdialyzed corpora lutea. Theriogenology 72, 528–534.
| Effects of human chorionic gonadotrophin on luteal blood flow and progesterone secretion in cows and in vitro-microdialyzed corpora lutea.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXptl2nsrY%3D&md5=2a0ebd214f4f10c09a06fd6cfdc695d6CAS | 19515407PubMed |
Burke, C. R., Mihm, M., Macmillan, K. L., and Roche, J. F. (1994). Some effects of prematurely elevated concentrations of progesterone on luteal and follicular characteristics during the oestrous cycle in heifers. Anim. Reprod. Sci. 35, 27–39.
| Some effects of prematurely elevated concentrations of progesterone on luteal and follicular characteristics during the oestrous cycle in heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2cXktVWhtLo%3D&md5=1d73f71ad6cbf03645a231a00a4542a9CAS |
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=64ca51d0d9b619dd0572e72474aeae4aCAS | 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=848c17a8c73164b01bb38d7aaaccb1e7CAS | 15935842PubMed |
Chan, C. C., Ng, E. H., Chan, M. M., Tang, O. S., Lau, E. Y., Yeung, W. S., and Ho, P. C. (2003). Bioavailability of hCG after intramuscular or subcutaneous injection in obese and non-obese women. Hum. Reprod. 18, 2294–2297.
| Bioavailability of hCG after intramuscular or subcutaneous injection in obese and non-obese women.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXovVekt7s%3D&md5=9d1352d25446a2faf1daf816cdf1b1d4CAS | 14585876PubMed |
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=6038faeaab282ac53cbf3ad10c7005d7CAS | 19556439PubMed |
Cole, L. A. (2010). Biological functions of hCG and hCG-related molecules. Reprod. Biol. Endocrinol. 8, 102.
| Biological functions of hCG and hCG-related molecules.Crossref | GoogleScholarGoogle Scholar | 20735820PubMed |
De Rensis, F., López-Gatius, F., García-Ispierto, I., and Techakumpu, M. (2010). Clinical use of human chorionic gonadotrophin in dairy cows: an update. Theriogenology 73, 1001–1008.
| Clinical use of human chorionic gonadotrophin in dairy cows: an update.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXktlClu74%3D&md5=46d6c317ee7717eb364c14a20be1e34bCAS | 20116839PubMed |
Diaz, T., Schmitt, E. J., de la Sota, R. L., Thatcher, M. J., and Thatcher, W. W. (1998). Human chorionic gonadotrophin-induced alterations in ovarian follicular dynamics during the oestrous cycle of heifers. J. Anim. Sci. 76, 1929–1936.
| 1:CAS:528:DyaK1cXkvV2ht7s%3D&md5=7fe483579b3cacf7b053543165fb6118CAS | 9690649PubMed |
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 gonadotrophin on cell populations in the ovine corpus luteum. Biol. Reprod. 38, 413–421.
| Effect of luteinizing hormone and human chorionic gonadotrophin on cell populations in the ovine corpus luteum.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1cXhs1Wrs7w%3D&md5=97a46d4addaf9226f06b789febb52e1cCAS | 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=b886d18b83f7eafebec7bdb868eac690CAS | 19553605PubMed |
Forde, N., Carter, F., Spencer, T. E., Bazer, F. W., Sandra, O., Mansouri-Attia, N., Okumu, L. A., McGettigan, P. A., Mehta, J. P., McBride, R., O’Gaora, P., Roche, J. F., and Lonergan, P. (2011). Conceptus-induced changes in the endometrial transcriptome: how soon does the cow know she is pregnant? Biol. Reprod. 85, 144–156.
| Conceptus-induced changes in the endometrial transcriptome: how soon does the cow know she is pregnant?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXotFOlsL4%3D&md5=11f719f39ba17575fcafd885e45e10b9CAS | 21349821PubMed |
Funston, R. N., Lipsey, R. J., Geary, T. W., and Roberts, A. J. (2005). Effect of administration of human chorionic gonadotrophin 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=b619516562b990f139fffc160630e255CAS | 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 gonadotrophin. J. Dairy Sci. 89, 2056–2064.
| Embryo survival from gossypol-fed heifers after transfer to lactating cows treated with human chorionic gonadotrophin.Crossref | GoogleScholarGoogle Scholar | 16702269PubMed |
Garrett, J. E., Geisert, R. D., Zavy, M. T., Gries, L. K., Wettemann, R. P., and Buchanan, D. S. (1988a). Effect of exogenous progesterone on prostaglandin F2α release and the interestrous interval in the bovine. Prostaglandins 36, 85–96.
| Effect of exogenous progesterone on prostaglandin F2α release and the interestrous interval in the bovine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1cXlt1aktr4%3D&md5=3cb4e90f75fd1d27fdf2ebce2be96170CAS | 3175025PubMed |
Garrett, J. E., Geisert, R. D., Zavy, M. T., and Morgan, G. L. (1988b). 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=51f14d4d7c21acf4ea8c311186fbf6fdCAS | 3199361PubMed |
Ginther, O. J. (1970). Effect of progesterone on length of oestrous cycle in cattle. Am. J. Vet. Res. 31, 493–496.
| 1:CAS:528:DyaE3cXht12jtb8%3D&md5=afd2e49be5cc361c71d189e66ab9d154CAS | 5462750PubMed |
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=84d6be7fb8cd3c5df4d2de97ee902088CAS | 15823350PubMed |
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=41fe350a21e89f20dad77ab7443f80d1CAS | 16728022PubMed |
Lonergan, P. (2011). Influence of progesterone on oocyte quality and embryo development in cows. Theriogenology 76, 1594–1601.
| Influence of progesterone on oocyte quality and embryo development in cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhsVanurzI&md5=15dc7ed19b3ee1cf310458ebea657936CAS | 21855985PubMed |
Macmillan, K. L., and Peterson, A. J. (1993). A new intravaginal progesterone-releasing device for cattle (CIDR-B) for oestrous synchronisation, increasing pregnancy rates and the treatment of post-partum anoestrus. Anim. Reprod. Sci. 33, 1–25.
| A new intravaginal progesterone-releasing device for cattle (CIDR-B) for oestrous synchronisation, increasing pregnancy rates and the treatment of post-partum anoestrus.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=1c1bf9c14e2a7b3dd6b8b3c99e5f233eCAS |
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=b545fdf35d84489e41fc999f449370f4CAS | 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=f89b4c069e16a80fbf669bdb2975a500CAS | 16207495PubMed |
Nascimento, A. B., Souza, A. H., Guenther, J. N., Dalla Costa, F. P., Sartori, R., and Wiltbank, M. C. (2012). Effects of treatment with human chorionic gonadotrophin or intravaginal progesterone-releasing device after AI on circulating progesterone concentrations in lactating dairy cows. Reprod. Fertil. Dev. , .
| Effects of treatment with human chorionic gonadotrophin or intravaginal progesterone-releasing device after AI on circulating progesterone concentrations in lactating dairy cows.Crossref | GoogleScholarGoogle Scholar | 23058209PubMed |
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=771f152e14989419844f5fc62c0d4acaCAS | 12374129PubMed |
Niswender, G. D., Roess, D. A., Sawyer, H. R., Silvia, W. J., and Barisas, B. G. (1985). Differences in the lateral mobility of receptors for luteinizing hormone (LH) in the luteal cell plasma membrane when occupied by ovine LH versus human chorionic gonadotrophin. Endocrinology 116, 164–169.
| Differences in the lateral mobility of receptors for luteinizing hormone (LH) in the luteal cell plasma membrane when occupied by ovine LH versus human chorionic gonadotrophin.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2MXls1CrtQ%3D%3D&md5=918f307ed1aca871f83f91d1c96d94a4CAS | 2981063PubMed |
Niswender, G. D., Juengel, J. L., Silva, P. J., Rollyson, M. K., and McIntush, E. W. (2000). Mechanisms controlling the function and life span of the corpus luteum. Physiol. Rev. 80, 1–29.
| 1:CAS:528:DC%2BD3cXmtl2jtg%3D%3D&md5=91ddbc1f315590184628584a11c89369CAS | 10617764PubMed |
O’Hara, L., Forde, N., Carter, F., Rizos, D., Maillo, V., Ealy, A. D., Kelly, A. K., Rodriguez, P., Isaka, N., Evans, A. C. O., and Lonergan, P. (2012a). Paradoxical effect of supplementary progesterone on corpus luteum function and conceptus development in cattle. Reproduction , .
| 22367589PubMed |
O’Hara, L., Scully, S., Maillo, V., Kelly, A. K., Duffy, P., Carter, F., Forde, N., Rizos, D., and Lonergan, P. (2012b). Effect of follicular aspiration just before ovulation on corpus luteum characteristics, circulating progesterone concentrations and uterine receptivity in single-ovulating and superstimulated heifers. Reproduction 143, 673–682.
| Effect of follicular aspiration just before ovulation on corpus luteum characteristics, circulating progesterone concentrations and uterine receptivity in single-ovulating and superstimulated heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XnvFKqsL8%3D&md5=6c989b72ca8cd1edd2a0315bb173509fCAS | 22367589PubMed |
Pope, W. F., Cárdenas, H., Wiley, T. M., and McClure, K. E. (1995). Dose-response relationships of exogenous progesterone shortly after ovulation on oestrous cycle length, blastocyst development and fertility in sheep. Anim. Reprod. Sci. 38, 109–117.
| Dose-response relationships of exogenous progesterone shortly after ovulation on oestrous cycle length, blastocyst development and fertility in sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXlt1ertrc%3D&md5=841c8c941de6edfaeaaf5601bb9c5981CAS |
Rizos, D., Scully, S., Kelly, A. K., Ealy, A. D., Moros, R., Duffy, P., Al Naib, A., Forde, N., and Lonergan, P. (2012). Effects of human chorionic gonadotrophin administration on Day 5 after oestrus on corpus luteum characteristics, circulating progesterone and conceptus elongation in cattle. Reprod. Fertil. Dev. 24, 472–481.
| Effects of human chorionic gonadotrophin administration on Day 5 after oestrus on corpus luteum characteristics, circulating progesterone and conceptus elongation in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38Xjs1Wqsbo%3D&md5=9ed884b2b02064c80dc0e9d3f3e2ca15CAS | 22401279PubMed |
Saleh, M., Shahin, M., Wuttke, W., Gauly, M., and Holtz, W. (2012). Pharmacokinetics of human chorionic gonadotrophin after i.m. administration in goats (Capra hircus). Reproduction 144, 77–81.
| Pharmacokinetics of human chorionic gonadotrophin after i.m. administration in goats (Capra hircus).Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhtV2ht7vO&md5=7d760132bc94793f583ba1b035217296CAS | 22573828PubMed |
Santos, J. E., Thatcher, W. W., Pool, L., and Overton, M. W. (2001). Effect of human chorionic gonadotrophin 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=a508905801848adf77828fe05afd95fdCAS | 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=f822109fca14186f94595e90d9955f9fCAS | 16707766PubMed |
Schmitt, E. J., Barros, C. M., Fields, P. A., Fields, M. J., Diaz, T., Kluge, J. M., and Thatcher, W. W. (1996a). A cellular and endocrine characterization of the original and induced corpus luteum after administration of a gonadotrophin-releasing hormone agonist or human chorionic gonadotrophin on Day 5 of the oestrous cycle. J. Anim. Sci. 74, 1915–1929.
| 1:CAS:528:DyaK28XltVSgu7s%3D&md5=33d5b0d05985d32f8b386232e5b6505bCAS | 8856446PubMed |
Schmitt, E. J., Diaz, T., Barros, C. M., de la Sota, R. L., Drost, M., Fredriksson, E. W., Staples, C. R., Thorner, R., and Thatcher, W. W. (1996b). Differential response of the luteal phase and fertility in cattle following ovulation of the first-wave follicle with human chorionic gonadotrophin or an agonist of gonadotrophin-releasing hormone. J. Anim. Sci. 74, 1074–1083.
| 1:CAS:528:DyaK28XivVansbk%3D&md5=e710a4abd8f856982a5985baa7937dcaCAS | 8726740PubMed |
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 gonadotrophin-releasing hormone, human chorionic gonadotrophin and progesterone. J. Dairy Sci. 90, 331–340.
| Interventions after artificial insemination: conception rates, pregnancy survival and ovarian responses to gonadotrophin-releasing hormone, human chorionic gonadotrophin and progesterone.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXmsFSlsw%3D%3D&md5=261decf6ac5f4509c929a016b67b0ae2CAS | 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=050fa34e24ad7530890f3a05957e6561CAS | 16125563PubMed |
Torres, A., Silva, J. C., Deloche, M., Humblot, P., Horta, A., and Lopes-da-Costa, L. (2013). Secondary corpora lutea induced by hCG treatment enhanced demi-embryo survival in lactating high-yielding dairy cows. Reprod. Domest. Anim. , .
| Secondary corpora lutea induced by hCG treatment enhanced demi-embryo survival in lactating high-yielding dairy cows.Crossref | GoogleScholarGoogle Scholar | 23320918PubMed |
Van Cleeff, J., Macmillan, K. L., Drost, M., Lucy, M. C., and Thatcher, W. W. (1996). Effects of administering progesterone at selected intervals after insemination of synchronized heifers on pregnancy rates and resynchronization of returns to service. Theriogenology 46, 1117–1130.
| Effects of administering progesterone at selected intervals after insemination of synchronized heifers on pregnancy rates and resynchronization of returns to service.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD28zgtVOgsg%3D%3D&md5=b5f0db99e0fbd839f26249443ce16383CAS | 16727976PubMed |
Vasconcelos, J. L., Sá Filho, O. G., Justolin, P. L., Morelli, P., Aragon, F. L., Veras, M. B., and Soriano, S. (2011). Effects of postbreeding gonadotrophin treatments on conception rates of lactating dairy cows subjected to timed artificial insemination or embryo transfer in a tropical environment. J. Dairy Sci. 94, 223–234.
| Effects of postbreeding gonadotrophin treatments on conception rates of lactating dairy cows subjected to timed artificial insemination or embryo transfer in a tropical environment.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXjslCnt7k%3D&md5=dddd0692c1f4feb844b0effd3ae64cd7CAS | 21183033PubMed |
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 gonadotrophin 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 gonadotrophin 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=5371122bb005189b59350f0fb5127cb1CAS | 21295842PubMed |
Wiltbank, M. C., Sartori, R., Herlihy, M. M., Vasconcelos, J. L. M., Nascimento, A. B., Souza, A. H., Ayres, H., Cunha, A. P., Keskin, A., Guenther, J. N., and Gumen, A. (2011). Managing the dominant follicle in lactating dairy cows. Theriogenology 76, 1568–1582.
| Managing the dominant follicle in lactating dairy cows.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3MbnvVCmsA%3D%3D&md5=8da89edcf36f5f4fa78232b2edb96159CAS | 21958644PubMed |
