Pregnancy establishment and maintenance after the administration of equine chorionic gonadotropin (eCG) associated or not with gonadotropin-releasing hormone (GnRH) after insemination in sheep
C. García-Pintos A and A. Menchaca A BA Instituto de Reproducción Animal Uruguay, Fundación IRAUy, Camino Cruz del Sur 2250, Montevideo, Uruguay.
B Corresponding author. Email: menchaca.alejo@gmail.com
Animal Production Science 58(10) 1802-1806 https://doi.org/10.1071/AN16489
Submitted: 25 July 2016 Accepted: 5 May 2017 Published: 6 June 2017
Abstract
It was recently demonstrated that equine chorionic gonadotropin (eCG) treatment 10 days after ovulation increases serum progesterone concentrations in sheep. The objective of the present study was to evaluate pregnancy outcomes induced with the administration of eCG and gonadotropin-releasing hormone (GnRH) after insemination. Three experiments were conducted in multiparous ewes that received fixed-time intrauterine insemination (Day 0) after a progesterone-based protocol for oestrus synchronisation. Experiment 1 consisted of 408 ewes, randomly assigned to three experimental groups; ewes in the first and second group received 400 IU of eCG on Day 5 and Day 10 after insemination respectively, while ewes on the third (control) group did not receive eCG. In Experiment 2, 587 ewes were randomly assigned to four experimental groups (2 × 2 factorial experiment), to receive or not 400 IU of eCG on Day 5, associated or not with 100 µg of GnRH analogue on Day 6 (i.e. 30 h after eCG administration). In Experiment 3, 715 ewes were randomly assigned to four experimental groups (2 × 2 factorial experiment), to receive or not 400 IU of eCG on Day 10, associated or not with 100 µg of GnRH analogue on Day 11 (i.e. 30 h after eCG administration). Pregnancy diagnosis was determined on Day 30 and Day 70 by ultrasonography. The eCG treatment after insemination failed to improve pregnancy outcomes in Experiments 1 and 2. However, in Experiment 3 the treatment with eCG on Day 10 enhanced pregnancy rate on Day 30, although this improvement was not maintained on Day 70, which showed greater pregnancy failure. The administration of GnRH on Day 6 or Day 11, preceded or not by eCG, did not affect any of the variables related to pregnancy. In summary, the improvement in progesterone profiles induced by eCG treatment on Day 10 after insemination, previously reported in sheep, seems to have a marginal positive effect on pregnancy establishment during the first month, which is not maintained during the second month of gestation.
Additional keywords: corpus luteum, embryonic mortality, fetal losses, PMSG.
References
Beck NFG, Peters AR, Williams SP (1994) The effect of GnRH agonist (buserelin) treatment on day 12 post mating on the reproductive performance of ewes. Animal Production 58, 243–247.Beck NFG, Jones M, Davies B, Mann GE, Peters AR (1996) The effect of GnRH analogue (buserelin) treatment on day 12 post mating on ovarian structures and plasma progesterone and oestradiol-17β concentrations in ewes. Animal Science 63, 407–412.
| The effect of GnRH analogue (buserelin) treatment on day 12 post mating on ovarian structures and plasma progesterone and oestradiol-17β concentrations in ewes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXhtFCkurg%3D&md5=95e8f1a86458bebeba0f0327d28e01f5CAS |
Bridges P, Wright D, Bufond W, Ahmad N, Hernandez Fonseca H, McCormick M, Schrick F, Dailey R, Lewis P, Inskeep E (2000) Ability of induced corpora lutea to maintain pregnancy in beef cows. Journal of Animal Science 78, 2942–2949.
| Ability of induced corpora lutea to maintain pregnancy in beef cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXnslKrur4%3D&md5=244f7161a52a447592b1ebf48cfa64e7CAS |
Cam MA, Kuran M, Yildiz S, Selcuk E (2002) Fetal growth and reproductive performance in ewes administered GnRH agonist on day 12 post-mating. Animal Reproduction Science 72, 73–82.
| Fetal growth and reproductive performance in ewes administered GnRH agonist on day 12 post-mating.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XltFahsL0%3D&md5=77313c0f8db99705566afbb827ea2791CAS |
Diskin MG, Morris DG (2008) Embryonic and early foetal losses in cattle and other ruminants. Reproduction in Domestic Animals 43, 260–267.
| Embryonic and early foetal losses in cattle and other ruminants.Crossref | GoogleScholarGoogle Scholar |
Diskin MG, Parr MH, Morris DG (2012) Embryo death in cattle: an update. Reproduction, Fertility and Development 24, 244–251.
| Embryo death in cattle: an update.Crossref | GoogleScholarGoogle Scholar |
García-Pintos C, Menchaca A (2016) Luteal response and follicular dynamics induced with equine chorionic gonadotropin (eCG) administration after insemination in sheep. Small Ruminant Research 136, 202–207.
| Luteal response and follicular dynamics induced with equine chorionic gonadotropin (eCG) administration after insemination in sheep.Crossref | GoogleScholarGoogle Scholar |
Johnson SK, Dailey RA, Inskeep EK, Lewis PE (1996) Effect of peripheral concentrations of progesterone on follicular growth and fertility in ewes. Domestic Animal Endocrinology 13, 69–79.
| Effect of peripheral concentrations of progesterone on follicular growth and fertility in ewes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28Xhs1Sgt7c%3D&md5=bede0f92c266d3f0ae88ec918ed6dcb3CAS |
Khan TH, Beck NFG, Khalid M (2007) The effects of GnRH analogue (buserelin) or hCG (chorulon) on Day 12 of pregnancy on ovarian function plasma hormone concentrations conceptus growth and placentation in ewes and ewe lambs. Animal Reproduction Science 102, 247–257.
| The effects of GnRH analogue (buserelin) or hCG (chorulon) on Day 12 of pregnancy on ovarian function plasma hormone concentrations conceptus growth and placentation in ewes and ewe lambs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtFKiurvK&md5=9b5dee8763841713a992e48032c4edacCAS |
Lonergan P, Forde N (2014) Maternal-embryo interaction leading up to the initiation of implantation of pregnancy in cattle. Animal 8, 64–69.
| Maternal-embryo interaction leading up to the initiation of implantation of pregnancy in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXotF2qt78%3D&md5=6ec4249d2e2513374406d14ef3ff870cCAS |
Mann GE, Lamming GE (2000) Effect of continuous infusion of a GnRH agonist (buserelin) on ovarian hormone secretion and estrous cycle length in cows. Theriogenology 54, 219–227.
| Effect of continuous infusion of a GnRH agonist (buserelin) on ovarian hormone secretion and estrous cycle length in cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXntFOhtb0%3D&md5=3d4e48a29cb9efab904149f9f549297dCAS |
Murphy BD (2012) Equine chorionic gonadotropin: an enigmatic but essential tool. Animal Reproduction 9, 223–230.
Núñez R, de Castro T, Cutaia L, Bó G, Menchaca A (2011) Pregnancy rates after administration of equine chorionic gonadotrophin (eCG) at progesterone intravaginal device removal and 14 days after fixed-time AI in beef cattle. Reproduction, Fertility and Development 23, 163
| Pregnancy rates after administration of equine chorionic gonadotrophin (eCG) at progesterone intravaginal device removal and 14 days after fixed-time AI in beef cattle.Crossref | GoogleScholarGoogle Scholar |
O’Hara L, Forde N, Duffy P, Randi F, Kelly AK, Valenza A, Rodriguez P, Lonergan P (2016) Effect of combined exogenous progesterone with luteotrophic support via equine chorionic gonadotrophin (eCG) on corpus luteum development, circulating progesterone concentrations and embryo development in cattle. Reproduction, Fertility and Development 28, 269–277.
| Effect of combined exogenous progesterone with luteotrophic support via equine chorionic gonadotrophin (eCG) on corpus luteum development, circulating progesterone concentrations and embryo development in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC28XhtFOjtrg%3D&md5=344f34cda0353255c88b16c7ecdd5c23CAS |
Parr RA, Davis IF, Fairclough RJ, Miles MA (1987) Overfeeding during early pregnancy reduces peripheral progesterone concentrations and pregnancy rate in sheep. Journal of Reproduction and Fertility 80, 317–320.
| Overfeeding during early pregnancy reduces peripheral progesterone concentrations and pregnancy rate in sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2sXktVWjtb4%3D&md5=9d5f3825e8e4ac37fb4a3faeb2dd6c48CAS |
Pritchard JY, Schrick FN, Inskeep EK (1994) Relationship of pregnancy rate to peripheral concentrations of progesterone and estradiol in beef cows. Theriogenology 42, 247–259.
| Relationship of pregnancy rate to peripheral concentrations of progesterone and estradiol in beef cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2cXmslantbg%3D&md5=fa04d2b4415cffb6a52016962d62633aCAS |
Quinlivan TD (1966) Estimates of pre- and perinatal mortality in the New Zealand Romney Marsh ewe. Journal of Reproduction and Fertility 11, 379–390.
| Estimates of pre- and perinatal mortality in the New Zealand Romney Marsh ewe.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaF287ls1GrsQ%3D%3D&md5=5e139a79469c63ec07a045023ac1e9e3CAS |
Sartori R, Bastos MR, Wiltbank MC (2010) Factors affecting fertilisation and early embryo quality in single- and superovulated dairy cattle. Reproduction, Fertility and Development 22, 151–158.
| Factors affecting fertilisation and early embryo quality in single- and superovulated dairy cattle.Crossref | GoogleScholarGoogle Scholar |
Spencer TE, Johnson GA, Bazer FW, Burghardt RC (2004) Implantation mechanisms: insights from the sheep. Reproduction 128, 657–668.
| Implantation mechanisms: insights from the sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtFSlsw%3D%3D&md5=203718e0def2d514ca3777e646f122baCAS |
StataCorp (2015) ‘Stata statistical software, release 13.’ (StataCorp LP: College Station, TX)
Thatcher WW, Macmillan KL, Hansen PJ, Drost M (1989) Concepts for regulation of corpus luteum function by the conceptus and ovarian follicles to improve fertility. Theriogenology 31, 149–164.
| Concepts for regulation of corpus luteum function by the conceptus and ovarian follicles to improve fertility.Crossref | GoogleScholarGoogle Scholar |
Wiltbank MC, Baez GM, Garcia-Guerra A, Toledo MZ, Monteiro PLJ, Melo LF, Ochoa JC, Santos JEP, Sartori R (2016) Pivotal periods for pregnancy loss during the first trimester of gestation in lactating dairy cows. Theriogenology 86, 239–253.
| Pivotal periods for pregnancy loss during the first trimester of gestation in lactating dairy cows.Crossref | GoogleScholarGoogle Scholar |