Pregnant Mares' Serum Gonadotropin (PMSG), also known as equine chorionic gonadotropin (eCG), is a hormone produced by the endometrial cups of pregnant mares. This hormone is primarily responsible for stimulating ovarian follicular development and supporting the formation of secondary corpora lutea during early gestation in horses. PMSG has both luteinizing and follicle-stimulating hormone activity, contributing to the maintenance of pregnancy. In veterinary and reproductive studies, PMSG is utilized to induce estrus and ovulation in various animal species due to its gonadotropic properties. This page compiles peer-reviewed research studies and scholarly articles that explore the biological function, application, and effects of Pregnant Mares' Serum Gonadotropin in equine reproduction and management.
Thompson RE, Meyers MA, Palmer J, Veeramachaneni DNR, Magee C, de Mestre AM, Antczak DF, Hollinshead FK.The equine chorionic girdle is comprised of specialized invasive trophoblast cells that begin formation approximately 25 days after ovulation (day 0) and invade the endometrium to become endometrial cups. These specialized trophoblast cells transition from uninucleate to differentiated binucleate trophoblast cells that secrete the glycoprotein hormone equine chorionic gonadotropin (eCG; formerly known as pregnant mare serum gonadotropin or PMSG). This eCG has LH-like activity in the horse but variable LH- and FSH-like activity in other species and has been utilized for these properties both in...
Ginther OJ.Examples of research discoveries and first reports on mare reproduction by the O.J. Ginther team are (1) determined daily circulating concentrations of four hormones during the estrous cycle, (2) showed that mares can be induced to ovulate and superovulate by hormone treatment during both ovulatory and anovulatory seasons, (3) demonstrated that prostaglandin F2α was the luteolysin in mares, (4) described the mare's elaborate hormonal and biochemical mechanism for selecting the ovulatory follicle from a pool of like follicles, (5) developed the method for diagnosing fetal sex by Day 60 using l...
The protein journalJanuary 18, 2023
Volume 42, Issue 1 24-36 doi: 10.1007/s10930-023-10092-x
Rodríguez MC, Mussio PE, Villarraza J, Tardivo MB, Antuña S, Fontana D, Ceaglio N, Prieto C.Equine chorionic gonadotropin (eCG) is a glycoprotein hormone widely used in timed artificial ovulation (TAI) and superovulation protocols to improve the reproductive performance in livestock. Until recently, the only eCG products available in the market for veterinary use consisted in partially purified preparations of pregnant mare serum gonadotropin (PMSG). Here, a bioactive recombinant eCG (reCG) produced in suspension CHO-K1 cells was purified employing different chromatographic methods (hydrophobic interaction chromatography and reverse-phase (RP)-HPLC) and compared with a RP-HPLC-purifi...
Uchida M, Addai-Arhin S, Ishibashi H, Hirano M, Fukushima S, Ishibashi Y, Tominaga N, Arizono K.Equine estrogens (EQs) are steroidal hormones isolated from the urine of pregnant mares and are used in the formulation of human medications. This study initially investigated the embryonic developmental toxicity of equilin (Eq) and equilenin (Eqn) in medaka (Oryzias latipes). Malformations were observed in embryos exposed to nominal concentrations of 1 and 10 mg/L of Eq and Eqn. Delayed hatching was observed at 1 mg/L of Eq. To further investigate the molecular mechanism of developmental toxicity caused by Eq and Eqn, transcriptome and bioinformatics analyses were performed. Among 2016 and ...
Aragunde Vieytes R, Viñoles Gil C, Gastal GDA, Cavestany D.In order to assess the effect of equine chorionic gonadotropin (eCG) administered on Day 5 or 7 of a fixed-time artificial insemination protocol (FTAI) in anestrous suckled beef cows, two experiments were performed to determine the following endpoints: Experiment 1 (n = 22), preovulatory follicle (POF) diameter, ovulation time, corpus luteum (CL) area, estradiol (E2) and progesterone (P4) concentrations; and Experiment 2 (n = 676), a field trial to evaluate conception rate using the same experimental design. In both experiments, a synchronization protocol using estradiol benzoate (EB) (Day...
Crowell CN, Fenton JM, Perry EB.Gustatory and olfactory changes have been reported during gestation in multiple species. However, few data are available regarding feeding preferences in gestating mares. The objective of this research was to evaluate the effect of oil-based palatants on feeding behavior in late term gestating mares. Late-term gestating mares (n = 5) and reproductively sound, open mares (n = 4) were evaluated via paired preference testing during the final 120 days of gestation. Oil-based flavors (corn oil, anise, and apple) were topically applied to a basal pelleted diet (0.375 ml/0.23 kg). Diets were offe...
Sielhorst J, Roggel-Buecker U, Neudeck KC, Kahler A, Rohn K, Luettgenau J, Bollwein H, Hollinshead F, Sieme H.The aim of this double-blinded placebo-controlled study was to investigate the effect of acetylsalicylic acid (ASA) on uterine blood flow, gestation length, placental and foal weights in pregnant mares. Sixteen Thoroughbred mares of different age (13.3 ± 4.1) and parity (7.4 ± 3.1) were randomly assigned to three treatment groups. Mares in group C (n = 4) served as controls and received 5,000 mg lactose orally once daily from D 120 (D 0 = day of ovulation) until parturition. Mares in group ASA1 (n = 7) received 5,000 mg ASA orally once daily from D 120 until parturition. Mares in group...
Castro T, Jacob JC, Domingues RR, Ginther OJ.Prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α) are involved in equine embryo mobility throughout the uterus on Days 11-15 (ovulation = Day 0). On a day (Day 12) of maximal embryo mobility in pregnant mares (n = 13) and before luteolysis in nonbred mares (n = 10), gene expressions were compared between the uterine horns that did and did not contain the mobile embryo and between pregnant and nonbred mares. A cytobrush was used to collect an endometrial sample from the middle of each uterine horn. In nonbred mares, there was no difference for any of the considered gene expressions ...
Shorten PR, Legacki EL, Chavatte-Palmer P, Conley AJ.Hormone secretion by the maternal ovaries, trophoblast/placenta and fetus occurs sequentially, creating distinct steroid metabolomic 'signatures' in systemic blood of pregnant mares that vary with gestational stage. Algorithms were developed to predict the gestational day (GD) from the maternal steroid metabolome (nine steroids; pregnenolone (P5), progesterone (P4), 5α-dihydroprogesterone (DHP), 17α-hydroxyprogesterone, allopregnanolone, 20α-hydroxy-DHP, 3β,20α-dihydroxy-DHP, DHEA and androstenedione) determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) of eight thoroug...
Ginther OJ.After the cessation of equine embryo mobility (fixation) on mean Day 16, the embryonic vesicle is rotated or oriented so that the pole with the embryo proper is opposite to the mesometrial attachment. Orientation involves massage of the vesicle by contractions of the turgid uterine horn and greater thickening of the vesicle at the pole with the embryo proper. Thickening of the dorsal endometrium (encroachment) especially on each side of the mesometrial attachment accounts for a guitar-pick shape of the vesicle when viewed in cross section of the uterine horn. On Days 21-40, the allantoic sac e...
Chavatte-Palmer P, Derisoud E, Robles M.Horses have been domesticated by man and historical information mostly associates horses with men. Nowadays, however, horse riding is essentially by women. Women are also very much involved in equine sciences, with a large contribution to the understanding of fetoplacental development. While highlighting the work of female scientists, this review describes the recent advances in equine fetoplacental studies, focusing on data obtained by new generation sequencing and progress on the understanding of the role of placental progesterone metabolites throughout gestation. A second emphasis is made o...
Lutzer A, Nagel C, Murphy BA, Aurich J, Wulf M, Gautier C, Aurich C.Blue light directed at 1 eye advances the equine ovulatory season but may also advance foaling. In this study, effects of blue LED light on pregnancy outcome were assessed. A total of 20 mares with singleton pregnancies were studied over 2 consecutive years in a cross-over design. In 1 year, mares received an extended photoperiod using 50 lux of blue LED light (468 nm) directed at a single eye from 08:00 until 23:00 daily via head-worn light masks starting mid-December and in the other year remained untreated as controls. Gestation was shorter in blue LED light-treated than in control pregnan...
Segabinazzi LGTM, Oba E, Alvarenga MA.Equine practitioners often prescribe the combined use of hCG and GnRH to hasten ovulation due to presumed synergistic effects. Therefore, this study aimed to test whether the combination of hCG and deslorelin acetate to hasten ovulation in mares would show any effect in inducing ovulation more efficiently than when either drug is used by itself, and to verify whether this association would affect progesterone concentrations; corpus luteum (CL) diameter and blood flow; and pregnancy outcome in recipient mares after embryo transfer (ET). Seventeen mares had the ovulation hastened (≥35 mm folli...
Villarraza CJ, Antuña S, Tardivo MB, Rodríguez MC, Mussio P, Cattaneo L, Fontana D, Díaz PU, Ortega HH, Tríbulo A, Macagno A, Bó GA, Ceaglio N....Equine chorionic gonadotropin (eCG) is a heterodimeric glycoprotein hormone produced by pregnant mares that has been used to improve reproductive performance in different domestic species. Several strategies to produce the hormone in a recombinant way have been reported; nevertheless, no approach has been able to produce a recombinant eCG (reCG) with significant in vivo bioactivity or in sufficient quantities for commercial purposes. For this reason, the only current product available on the market consists of partially purified preparations from serum of pregnant mares (PMSG). Herein, we des...
Gáspárdy A, Renkó E, Somoskői B, Bába A, Cseh S.The objective of this study was to compare the efficiency of artificial insemination (AI) carried out with frozen and fresh, diluted and chilled semen under field conditions. One hundred and twenty-nine mares of different breeds were included in the study. Eighty-one out of the 107 mares inseminated with fresh, chilled semen got pregnant. Seven pregnant mares aborted and 74 foals were born. Out of the 22 mares inseminated with frozen semen, 17 mares got pregnant. Two mares out of the 17 pregnant mares aborted and finally 15 healthy foals were born. No difference was found between the two group...
Data in briefApril 25, 2020
Volume 30 105616 doi: 10.1016/j.dib.2020.105616
Nieto-Olmedo P, Gaitskell-Phillips G, Martín-Cano FE, Ortiz-Rodríguez JM, Peña FJ, Ortega-Ferrusola C.This article provides the dataset for the use of power Doppler ultrasound to assess the equine uterus from the recent research article titled "Power Doppler can detect the presence of 7-8 days conceptuses prior to flushing in an equine embryo transfer program"(1). The vascularization of the endometrium was objectively assessed in mares by quantification of pixels in bitmap format (BMP) using computer assisted analysis of images. Fifty-two mares were examined on days 7 (26 mares) and 8 (26 mares) post-ovulation prior to performing flushing procedures for embryo recovery. Receiver operating char...
Beachler TM, Gracz HS, Morgan DR, Bembenek Bailey SA, Borst L, Ellis KE, Von Dollen KA, Lyle SK, Nebel A, Andrews NC, Koipalli J, Gadsby JE, Bailey CS.Metabolomics may represent an avenue for diagnosis of equine ascending placentitis. Objective: To characterise the plasma metabolomic profile in healthy mares and mares with induced ascending placentitis, with the goal of identifying metabolites with potential clinical value for early diagnosis of placentitis. Methods: Controlled in vivo experiment. Methods: Placentitis was induced in 10 late-term pregnant pony mares via Streptococcal equi subsp. zooepidemicus inoculation in five mares between days 285 and 290 of gestation, while five mares served as healthy controls. Repeated ultrasound exami...
Pinto CRF.It has been more than a hundred years that studies aiming to elucidate the processes involved in cyclicity and pregnancy pointed out the requirement of ovaries and corpora lutea for embryo survival and pregnancy establishment. For horses, luteal progesterone is essential for pregnancy only during the first trimester. This progestational support is complex among domestic animals as ovarian luteal function is further enhanced by the LH-action role of equine chorionic gonadotropin (eCG) starting ∼ on Day 35 of pregnancy. Increased eCG secretion leads to the formation of supplementary corpora ...
El-Sheikh Ali H, Legacki EL, Scoggin KE, Loux SC, Dini P, Esteller-Vico A, Conley AJ, Stanley SD, Ball BA.Equine placentitis is associated with alterations in maternal peripheral steroid concentrations, which could negatively affect pregnancy outcome. This study aimed to elucidate the molecular mechanisms related to steroidogenesis and steroid-receptor signaling in the equine placenta during acute placentitis. Chorioallantois (CA) and endometrial (EN) samples were collected from mares with experimentally induced placentitis (n = 4) and un-inoculated gestationally age-matched mares (control group; n = 4). The mRNA expression of genes coding for steroidogenic enzymes (3βHSD, CYP11A1, CYP17A1, CYP19...
Wuri L, Agca C, Agca Y.This study compared the morphometric, subcellular characteristics, in vitro fertilisation (IVF) and embryonic developmental potential of metaphase II (MII) mouse oocytes obtained from females superovulated with either anti-inhibin serum-human chorionic gonadotrophin (AIS-hCG) or pregnant mare serum gonadotrophin (PMSG)-hCG. The oocyte's quantity, quality, zona pellucida (ZP) thickness, perivitelline space (PVS), diameter, microtubules, F-actin, cortical granules (CGs) and mitochondrial distribution were determined. Superovulation using AIS-hCG resulted in a higher numbers of oocyte/donor compa...
Manteca Vilanova X, De Briyne N, Beaver B, Turner PV.Collection of blood from pregnant mares for extraction of equine chorionic gonadotropin (eCG) is a critical but relatively unknown and poorly regulated practice in the countries in which it occurs. Equine chorionic gonadotropin is a hormone that is widely used to enhance reproductive performance and management of dairy and beef cattle, sheep, goats, and pigs kept under intensive housing systems. eCG is extracted from the blood of brood mares between days 40-120 of gestation. Although alternatives have been sought, there is currently no efficacious replacement, natural or synthetic, for eCG. Re...
Busse NI, Uberti B.A 12-year-old, multiparous, parturient show jumper embryo-recipient mare presented at a veterinary hospital, seven days past her due date and with a dilated cervix, for evaluation of mild colic. Gastrointestinal or metabolic abnormalities and fetal maldispositions were excluded as causes of dystocia, and a diagnosis of uterine inertia was made. There was no uterine response to oxytocin treatment. A live filly was delivered via C-section, and severe selenium deficiency was eventually confirmed in the mare, her offspring, and in the herd of origin. The filly was born with severe white muscle dis...
Morris LH, Maclellan LJ.The increased commercialisation of intracytoplasmic sperm injection (ICSI) in horses creates more opportunities to incorporate advanced reproductive technologies, such as sex-sorted, refrozen and lyophilised spermatozoa, into a breeding program. This paper reviews the status of these semen-handling technologies in light of their use in equine ICSI programs. Pregnancies have been achieved from each of these advanced technologies when combined with ICSI in horses, but refinements in the semen-handling processes underpinning these technologies are currently being explored to produce more reliable...
Ellerbrock RE, Curcio BR, Zhong L, Honoroto J, Wilkins P, Lima FS, Giguere S, Canisso IF.Enrofloxacin may be an alternative antimicrobial for unresponsive cases of severe bacterial infections in pregnant mares. As pregnancy may affect drug bioavailability, distribution, metabolism and excretion, dose adjustment might be necessary. Objective: To determine the disposition of orally and intravenously administered enrofloxacin in pregnant and non-pregnant mares. Methods: Randomised cross-over experiment. Methods: Six light-breed, healthy pregnant mares (260 days gestation) were given a single dose of either intravenous (5 mg/kg bwt) or oral compounded (7.5 mg/kg bwt) enrofloxacin, ...
Rahmani Shahraki A, Raisi A.One of the reasons of weight loss and poor performance in horses is decrease in food intake. Oral cavity problems can cause malfunctions in prehension and deglutition resulting in dysphagia. There are few published reports about a metallic foreign body disorders in the oral cavity of horses due to an important role of their flexible lip and incisor teeth in food selection and prehension. This report describes the history, clinical, hematological and radiographic findings and surgical management of a left oral wall fistula formation due to a piece of wire penetration in a pregnant mare. The wir...
Hannan MA, Haneda S, Itami Y, Wachi S, Saitoh T, Cheong SH, Nambo Y.There has been no report of equine embryo transfer in Japan for the last 24 years. Our objective was to establish an effective protocol for embryo transfer in domestic horse. A Hokkaido native pony was bred by deep-horn artificial insemination with frozen semen from a Connemara pony. Embryo collection was performed using a non-surgical method on day 7. Two embryos were obtained from three flushes (67% recovery) and were transferred fresh into crossbred recipient mares. Both recipient mares were diagnosed pregnant (100% pregnancy rate) 5 days after embryo transfer and had normal progesterone le...
Satué K, Marcilla M, Medica P, Ferlazzo A, Fazio E.Androgens modulate maternal ovarian activity, embryo implantation and correct placental development. The objective of this study was to establish reference values for testosterone (T), androstenedione (A4) and dehydroepiandrosterone (DHEA) concentrations in pregnant mares. A total of 30 healthy Spanish Purebred mares with an age range of 9.33 ± 3.31 years, were studied during the 11 months of gestation. T, A4 and DHEA concentrations were determined using EIA validated specifically for equines. T increased in the 2nd and 3rd month (P < 0.05), showing a plateau between the 4th and 6th m...
Cywes-Bentley C, Rocha JN, Bordin AI, Vinacur M, Rehman S, Zaidi TS, Meyer M, Anthony S, Lambert M, Vlock DR, Giguère S, Cohen ND, Pier GB.Immune correlates of protection against intracellular bacterial pathogens are largely thought to be cell-mediated, although a reasonable amount of data supports a role for antibody-mediated protection. To define a role for antibody-mediated immunity against an intracellular pathogen, Rhodococcus equi, that causes granulomatous pneumonia in horse foals, we devised and tested an experimental system relying solely on antibody-mediated protection against this host-specific etiologic agent. Immunity was induced by vaccinating pregnant mares 6 and 3 weeks prior to predicted parturition with a conjug...
Cywes-Bentley C, Rocha JN, Bordin AI, Vinacur M, Rehman S, Zaidi TS, Meyer M, Anthony S, Lambert M, Vlock DR, Giguère S, Cohen ND, Pier GB.Immune correlates of protection against intracellular bacterial pathogens are largely thought to be cell-mediated, although a reasonable amount of data supports a role for antibody-mediated protection. To define a role for antibody-mediated immunity against an intracellular pathogen, Rhodococcus equi, that causes granulomatous pneumonia in horse foals, we devised and tested an experimental system relying solely on antibody-mediated protection against this host-specific etiologic agent. Immunity was induced by vaccinating pregnant mares 6 and 3 weeks prior to predicted parturition with a conjug...
Bucca S, Fogarty U, Collins A, Small V.Ultrasound assessment of feto-placental well-being has found its application in the equine field, as a valid diagnostic tool. Most reports on equine fetal parameters focus on advanced to late gestation. The aim of the present study was to further validate the technique of ultrasound evaluation of the equine fetal environment, by extending its application to earlier stages of pregnancy. Fetal parameters were collected (on 150 pregnancies) over a 3-year period. Data included in the study were selected according to the clinical behaviour of the mare, the neonate/fetus and fetal membranes at the t...
LaPolt PS, Tilly JL, Aihara T, Nishimori K, Hsueh AJ.The actions of gonadotropins on ovarian differentiation are associated with dynamic changes in gonadotropin receptor content, presumably due to modulation of receptor gene expression. The present studies used a reverse transcription-polymerase chain reaction to obtain a rat FSH receptor cDNA fragment, followed by synthesis of a labeled cRNA probe to examine the regulation of FSH receptor mRNA levels during follicular maturation, ovulation, and luteinization. Northern blot analysis of ovarian RNA with the FSH receptor probe revealed two predominant hybridization signals of 7.0 and 2.5 kilobases...
Smits K, De Coninck DI, Van Nieuwerburgh F, Govaere J, Van Poucke M, Peelman L, Deforce D, Van Soom A.Although the equine oviduct clearly affects early embryo development and the selective transport of equine embryos through the oviduct indicates a reciprocal interaction, the influence of the embryo on gene expression in the oviduct remains to be determined in the horse. The aim of this study was to examine this by means of RNA sequencing. Four days after ovulation, epithelial cells ipsilateral and contralateral to the ovulation side from five cyclic and five pregnant mares were collected from the oviduct. RNA was extracted, samples were sequenced, and data analysis was performed to determine ...
Powell DG, Dwyer RM, Traub-Dargatz JL, Fulker RH, Whalen JW, Srinivasappa J, Acree WM, Chu HJ.To determine safety, immunogenicity, and efficacy of an inactivated equine rotavirus vaccine. Methods: Prospective randomized controlled trial. Methods: 316 pregnant Thoroughbred mares during the first year of the study and 311 during the second year. Methods: During the first year, mares received 3 doses of vaccine or placebo, IM, at 8, 9, and 10 months of gestation. Serum neutralizing antibody titers were measured before vaccination and 1 and 35 days after foaling. Antibody titers were measured in foals 1, 7, 35, 60, 90, and 120 days after birth. During the second year, mares that had been v...
Bielefeldt-Ohmann H, Prow NA, Wang W, Tan CS, Coyle M, Douma A, Hobson-Peters J, Kidd L, Hall RA, Petrovsky N.In 2011, following severe flooding in Eastern Australia, an unprecedented epidemic of equine encephalitis occurred in South-Eastern Australia, caused by Murray Valley encephalitis virus (MVEV) and a new variant strain of Kunjin virus, a subtype of West Nile virus (WNVKUN). This prompted us to assess whether a delta inulin-adjuvanted, inactivated cell culture-derived Japanese encephalitis virus (JEV) vaccine (JE-ADVAX™) could be used in horses, including pregnant mares and foals, to not only induce immunity to JEV, but also elicit cross-protective antibodies against MVEV and WNVKUN. Foals, 74...
Murphy BA, Walsh CM, Woodward EM, Prendergast RL, Ryle JP, Fallon LH, Troedsson MH.Artificial lighting is commonly used to advance the breeding season in horses. Light masks have been developed that direct light at a single eye to inhibit the production of melatonin, the decoder of photoperiod for seasonally breeding animals. Objective: To investigate whether low-intensity blue light from light masks was effective at advancing the breeding season in mares. Methods: Controlled experiment. Methods: Data on reproductive activity was collected from 3 groups of mares maintained on Kentucky horse farms under various lighting conditions between 20 November 2011 and 10 February 2012...
Nagel C, Erber R, Bergmaier C, Wulf M, Aurich J, Möstl E, Aurich C.The mechanisms leading to parturition in the horse in many aspects differ from those in other species. Pregnancy is maintained not by progesterone but by 5α-pregnanes and the progestin precursor pregnenolone originates from the fetus. As parturition approaches, the fetal adrenal switches from pregnenolone to cortisol synthesis but it is not known whether cortisol crosses the placenta. We hypothesized that in parallel to fetal cortisol release, cortisol in the maternal circulation increases before foaling and this increase can be determined in both saliva and plasma. In addition, maternal, fet...
Allen WR.Four separate components combine to produce the progesterone and biologically active 5 alpha-reduced pregnanes needed to maintain pregnancy in the mare. The primary corpus luteum (CL) is prolonged beyond its cyclical lifespan by the down-regulation of endometrial oxytocin receptors to prevent activation of the luteolytic pathway and its waning progesterone production is supplemented from day 40 of gestation by the formation of a series of accessory CL which develop in the maternal ovaries as a result of the gonadotrophic actions of pituitary FSH and the equine chorionic gonadotrophin (eCG). Fr...
Allen WR, Skidmore JA, Stewart F, Antczak DF.Measurement of the concentrations of equine chorionic gonadotrophin (eCG) in the serum of pregnant mares and Jenny donkeys carrying normal intraspecies and hybrid interspecies pregnancies suggested that the production of this hormone may be influenced by parental gene imprinting. Specifically, a differential expression of maternal and paternal genes may control the size and secretory activity of the structures that secrete eCG, the fetal endometrial cups. However, bisection of an interspecies mule embryo followed by transfer of the resulting demi-embryos and other intact mule embryos to horse ...
Sarkar DK, Smith GC, Fink G.We have investigated the effect of manipulating central catecholamines on the timing of puberty (as assessed by vaginal opening) in female rats and the surge of luteinizing hormone (LH) and gonadotropin releasing hormone (GnRH) induced by pregnant mare serum gonadotropin (PMSG) in immature female rats. Manipulation of the catecholamines was carried out with either 6-hydroxydopamine (6-OHDA) administered with or without either desipramine (DMI) or pargyline, or alpha-methyl-p-tyrosine (alpha-MPT). The neonatal administration of 6-OHDA delayed puberty, an effect which was potentiated by pretreat...
Manteca Vilanova X, De Briyne N, Beaver B, Turner PV.Collection of blood from pregnant mares for extraction of equine chorionic gonadotropin (eCG) is a critical but relatively unknown and poorly regulated practice in the countries in which it occurs. Equine chorionic gonadotropin is a hormone that is widely used to enhance reproductive performance and management of dairy and beef cattle, sheep, goats, and pigs kept under intensive housing systems. eCG is extracted from the blood of brood mares between days 40-120 of gestation. Although alternatives have been sought, there is currently no efficacious replacement, natural or synthetic, for eCG. Re...
Bazzano M, Giannetto C, Fazio F, Arfuso F, Giudice E, Piccione G.Pregnancy represents a specific physiological status characterized by continuous adjustments that affect maternal metabolism of all nutrients. In the last trimester of pregnancy, mare's nutrient requirements greatly increase and most pregnancy-associated diseases are likely to occur. Therefore, we aimed to assess the metabolic profile of broodmares focusing on the last 3 months of pregnancy and the early post-partum. Fifteen pregnant mares (Group A) were monitored from 263 ± 3 days of pregnancy until 21 days after foaling. Seven non-pregnant mares (Group B) were used as the control group...
Wooding FB, Morgan G, Fowden AL, Allen WR.Equine chorionic gonadotropin (eCG) production by the fetally derived endometrial cups appears to be necessary for the establishment and maintenance of normal equine pregnancy. Starting at about the 27th day of pregnancy, an equatorial band of trophectodermal cells on the surface of the spherical conceptus forms the chorionic girdle. This girdle consists initially of flat trophectodermal epithelium which corrugates into folds as the cells proliferate. The folds are then pressed against the uterine epithelium by expansion of the conceptus. The cells on the apices of the folds become binucleate ...
Mattison DR, White NB, Nightingale MR.The polycyclic aromatic hydrocarbon (PAH) benzo(a)pyrene (BP) reduced the fertility of DBA/2N mice in a dose-dependent fashion. Control mice produced offspring at a rate of 0.91 pups/mouse per week. Treatment with BP at doses of 10, 100, 200, and 500 mg/kg decreased offspring production rates to 0.61, 0.20, zero and zero pups/mouse per week, respectively. BP also destroyed primordial oocytes in similarly treated mice. Treatment with BP at doses of 10, 50, 100, and 500 mg/kg destroyed 20%, 58%, 88%, and 100%, respectively, of the primordial oocytes in DBA/2N mouse ovaries. Dose-response curves ...
Stewart F, Allen WR.The role of equine chorionic gonadotrophin (CG, formerly termed Pregnant Mare serum Gonadotrophin, PMSG) in maintaining equine pregnancy was investigated by examining the effects of this hormone on the maternal ovaries during early gestation and relating these findings to the receptor binding activities of CG in vitro. Measurement of plasma progestagen profiles in mares and donkeys carrying horse, donkey, mule ( female horse X male donkey) and hinny (female donkey X male horse) conceptuses confirmed that CG induced several secondary ovulations and thus maintained maternal progestagen concentra...
Putnam MR, Bransby DI, Schumacher J, Boosinger TR, Bush L, Shelby RA, Vaughan JT, Ball D, Brendemuehl JP.Effects of the endophyte Acremonium coenophialum in tall fescue on pregnant mares and foal viability were evaluated. Twenty-two mature pregnant mares were randomly chosen to graze either Kentucky-31 tall fescue that was free from A coenophialum (endophyte-free, EF) or tall fescue infected with A coenophialum (endophyte-present, EP) after the first 90 days of pregnancy through parturition. Concentrations of pyrrolizidine and ergopeptine alkaloids were significantly greater in EP grass, compared with EF pasture. Ten of 11 mares grazing EP pasture had obvious dystocia. Mean duration of gestation ...
Steger DJ, Altschmied J, Büscher M, Mellon PL.Primate and equine species are thought to be unique among mammals in synthesizing placental gonadotropin glycoprotein hormones. Human chorionic gonadotropin (CG) and equine pregnant mare's serum gonadotropin (PMSG) are produced in placenta by the specific activation of a glycoprotein hormone alpha-subunit gene and a corresponding beta-subunit gene. The evolutionary mechanisms for the apparently independent acquisition of tissue specificity were investigated by cloning the 5' flanking region of the equine alpha-subunit gene and comparing the DNA elements and trans-acting factors involved in pla...
Grünig G, Triplett L, Canady LK, Allen WR, Antczak DF.Invading trophoblasts form endometrial cups in the endometrium of the pregnant mare. In the present study we characterized the maternal leucocyte response to endometrial cups from their formation to their regression. The maternal leucocyte response was correlated with the stages of trophoblast development. (1) Aggregates of CD4+ and CD8+ cells were present between the migrating and differentiating endometrial cup trophoblasts and surrounding the forming endometrial cups. (2) Numbers of CD4+ cells within the mature endometrial cups were much reduced. At the periphery of the endometrial cups CD4...
Hoppen HO.Chorionic gonadotrophins seem to be unique for primate and equid species. Unlike primates, the equine conceptus does not implant in the maternal uterine endometrium until around day 37 of pregnancy. At this time specialized cells of the trophoblast, organized in the embryonic girdle, invade the endometrium and become established in the endometrial stroma, forming the so-called endometrial cups. This migration of girdle cells is accompanied by their morphological transformation into large decidual-like cells and by the appearance of a gonadotrophic hormone in the mare's blood. There is convinci...
Villarraza CJ, Antuña S, Tardivo MB, Rodríguez MC, Mussio P, Cattaneo L, Fontana D, Díaz PU, Ortega HH, Tríbulo A, Macagno A, Bó GA, Ceaglio N....Equine chorionic gonadotropin (eCG) is a heterodimeric glycoprotein hormone produced by pregnant mares that has been used to improve reproductive performance in different domestic species. Several strategies to produce the hormone in a recombinant way have been reported; nevertheless, no approach has been able to produce a recombinant eCG (reCG) with significant in vivo bioactivity or in sufficient quantities for commercial purposes. For this reason, the only current product available on the market consists of partially purified preparations from serum of pregnant mares (PMSG). Herein, we des...
Köhne M, Kuhl J, Ille N, Erber R, Aurich C.For prevention of early conceptus loss in the horse, treatment with progestins has become common practice. In cattle, treatment with human chorionic gonadotrophin (hCG) during the early postovulatory phase stimulates endogenous progesterone synthesis, which is an important factor for maintenance of early pregnancy via stimulation of endometrial function and conceptus development. In the present study we have therefore investigated the influence of treatment with hCG either for induction of ovulation or during the early luteal phase on plasma progestin concentrations, size of the corpus luteum ...
Brück I, Anderson GA, Hyland JH.The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the ...
Bondo T, Jensen SK.This study assessed the effect of a vitamin E supplement given to pregnant mares on immunoglobulins (Ig) levels in foals. In addition, the fatty acid (FA) content and composition of the mares' milk was assessed. Milk α-tocopherol concentrations were compared between pregnant Danish Warmblood mares (n = 17) given a daily oral supplement of 2500 international units (IU) RRR-α-tocopherol in the last 4 weeks of pregnancy and a group of unsupplemented mares (n = 17) receiving 170-320 IU vitamin E daily originating from the feed. Milk α-tocopherol was higher in supplemented mares (36.7, 12.4 and ...
Kindahl H, Knudsen O, Madej A, Edqvist LE.Blood samples from 4 mares during the late luteal phase, oestrus, early pregnancy and up to about 150 days of gestation were analysed for 15-keto-13,14-dihydroprostaglandin F-2 alpha (PGFM), progesterone, PMSG and oestrone sulphate by radioimmunoassays. During the late luteal phase, at the time of corpus luteum regression and decreasing progesterone levels, PGFM peaks were recorded. During early pregnancy (i.e. from mating and up to about Day 30) no such peaks were detected. After mating the progesterone levels increased and remained high throughout the observation period. During the oestrous ...
Sayasith K, Bouchard N, Doré M, Sirois J.The mammalian ovulatory process is accompanied by a gonadotropin-dependent increase in follicular levels of prostaglandin E2 (PGE2) and PGF2alpha, which are metabolized by 15-hydroxy prostaglandin dehydrogenase (PGDH). Little is known about ovarian PGDH regulation in non-primate species. The objectives of this study were to characterize the structure of equine PGDH and its regulation in follicles during human chorionic gonadotropin (hCG)-induced ovulation. The full-length equine PGDH was obtained by RT-PCR, 5'- and 3'-rapid amplification of cDNA ends (RACE). Its open reading frame encodes a 26...
