Pregnancy in horses, or equine gestation, is a physiological process that involves the development of a foal within the mare over approximately 11 months. This period is characterized by distinct stages, including fertilization, embryonic development, and fetal growth. Throughout gestation, mares undergo various physiological and hormonal changes to support the developing fetus. Monitoring pregnancy in horses involves assessing fetal health and mare well-being through veterinary examinations and diagnostic tools such as ultrasound. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological processes, management practices, and health considerations associated with equine pregnancy.
Aitken RJ, Lambourne S, Medica AJ.A capacity to predict the likelihood of pregnancy following natural matings would be of considerable benefit to the Thoroughbred horse breeding industry. In this article, we describe a strategy for achieving this outcome through the analysis of dismount samples, that achieved an overall accuracy of 94.6%. The purpose of this study was to determine whether the analysis of dismount semen samples from Thoroughbred stallions could be used to predict whether a given mating would result in a pregnancy. The analysis was based on 143 matings of 141 mares by a cohort of 7 Thoroughbred stallions over a ...
Donato GG, Appino S, Bertero A, Poletto ML, Nebbia P, Robino P, Varello K, Bozzetta E, Vincenti L, Nervo T.Mares' subfertility represents a complex diagnostic and therapeutic challenge and both clinical and subclinical endometritis are considered major causes of impaired fertility. Thanks to its properties, ozone has a big potential as a treatment for equine endometritis. Therefore, the aim of this study is to describe the safety and the effects on endometrium and reproductive parameters of mares of a commercial ozone foam preparation (Riger Spray®). Twenty-four mares were treated during estrus: ozone group with an intrauterine instillation of ozone foam preparation (OG, n=16) and control group wi...
Shilton CA, Kahler A, Roach JM, Raudsepp T, de Mestre AM.Embryonic and foetal loss remain one of the greatest challenges in equine reproductive health with 5-10% of established day 15 pregnancies and a further 5-10% of day 70 pregnancies failing to produce a viable foal. The underlying reason for these losses is variable but ultimately most cases will be attributed to pathologies of the environment of the developing embryo and later foetus, or a defect intrinsic to the embryo itself that leads to lethality at any stage of gestation right up to birth. Historically, much research has focused on the maternal endometrium, endocrine and immune responses ...
Poradowski D, Chrószcz A.The study consisted of the immunohistochemical analysis of fundic and pyloric mucosa in the equine stomach between the 4th and 11th month of gestation. The accessible material was classified into three age groups using the CRL method. The adult reference group was used to define potential differences between foetal and adult populations of gastric APUD cells. The samples were preserved, prepared, and stained according to the standard protocols. The immunohistochemical reaction was assessed using the semi-quantitative IRS method. The results were documented and statistically analysed. The most ...
Fedorka CE, Ali HE, Troedsson MHT.Galectins are a family of proteins that bind to glycans, acting in a cytokine-like manner throughout the body. In the majority of mammalians, galectins have been found to be involved in pregnancy maintenance, but few studies have evaluated this in the horse. Therefore, the objective of this study was to examine the expression of various galectins in pregnant and nonpregnant mares. Next-generation RNA sequencing was performed on the chorioallantois and endometrium of healthy pregnant mares at 120, 180, 300, and 330 days of gestation (n = 4/stage), as well as 45-day chorioallantois (n = 4), post...
Sobral GG, Gomes Neto OC, Carneiro GF.The objective of this study was to determine whether supplementation with Saccharomyces cerevisiae or β-glucan, in the maternal diet during late pregnancy affects the concentration of total IgG in the colostrum of mares and influences the concentration of IgG in its foals. A total of 21 pregnant mares were used, aged 6±2 years, 3±1 pregnancies, 450±50kg in weight, and they were distributed into three groups: the control group (n=7); the S. cerevisiae group (n=7), which received 10CFU of S. cerevisiae orally; and the β-glucan group (n=7), which received 0.35g of β-glucan orally. All group...
Tsogtgerel M, Murase H, Moriyama H, Sato F, Nambo Y.Late-term fetal loss in horses is a major problem in the horse-breeding industry globally. Abnormal pregnancies should be diagnosed as early as possible to prevent abortions and other gestational problems. According to our previous longitudinal study in healthy pregnant mares, the plasma activin A concentration increases as pregnancy progresses. The aim of the present study was to compare plasma activin A concentrations in healthy pregnant Thoroughbred mares (n=40) with those in pregnant mares that suffered fetal loss or showed abnormal symptoms (n=30) during late gestation. This field study f...
Ashraf R, Rashid S, Rasheed I, Asif S.This paper includes the study of early embryonic death (EED), predisposing factors of EED and treatment. EED refers to the fetal mortality which varies in mare and camelids but most probably not later than 50 days of gestation. This duration may be divided into very early mortality, early mortality and late embryonic mortality. This also varies in mare and camelids. There are different embryonic, maternal, environmental/external, and infectious and noninfectious factors which lead to early embryonic loss. Diagnosis is very difficult as in most of the cases resorption of fetus occurs but it is ...
Grabowska A, Kozdrowski R.Progesterone plays a crucial role in the maintenance of pregnancy from conception to about 100-120 days of gestation when placenta becomes the main source of gestagens. The aim of the study was to test progesterone concentration 14 days after ovulation in pregnant mares and relate it to peak estral endometrial edema and the presence of intrauterine fluid (IUF) after artificial insemination (AI), the number of treatments against IUF, and the time from AI to the day when the uterus was found free of fluid. Results: Mares were divided into two groups: group A (n = 13; age 10.8 ± 4.5 y...
Okada CTC, Kaps M, Reichart U, Walter I, Gautier C, Aurich J, Aurich C.While detrimental effects of reduced plasma progesterone concentration in the early luteal phase on conceptus development in horses have recently been demonstrated, there is no information on associated effects on the endometrium, allantochorion (AC), and chorionic girdle (CG) in this species. We hypothesised that reduced early postovulatory progesterone concentration in pregnant horses is detrimental to endometrial function and development of the embryonic membranes and is an underlying cause of delayed conceptus development. After insemination and ovulation, mares (n = 11) were assigned to...
Roach J, Arango Sabogal JC, Smith K, Foote A, Verheyen K, de Mestre AM.Risk factors associated with equine reproductive efficiency have been identified along with those associated specifically with early pregnancy loss (EPL). In contrast, no studies have reported risk factors associated with abortion (loss between day 70 and 300 post-cover). Given the causes of abortion differ to those of EPL, likely too will the risk factors. A retrospective cohort study was carried out to identify risk factors associated with abortion in UK and Irish based Thoroughbreds, collecting data on 20 exposure variables over a five-year period. A generalized linear mixed model was utili...
Poradowski D, Chrószcz A.Studies of equine stomach prenatal development are very rare, and descriptions usually focus on the processes taking place in the embryonic period. Only general information about gastric organogenesis in the fetal period is available in embryology textbooks on domestic mammals. The material for our study included twenty half-breed horse fetuses divided into three age groups on the basis of known fetal age (verified using the CRL method). Our study consists of the topographical, morphological, and morphometrical description of stomach development between the 4th and 11th months of gestation. Ev...
Martinez Zuviria S, Ciurkiewicz M, Wohlsein P, Madariaga G, Zuccolilli G.Cystic hygroma (hygroma cysticum) is a malformation that has not yet been described as a cause of early pregnancy loss in equines. The condition is a congenital anomaly occurring during embryogenesis due to a failure in which the primitive lymphatic sac does not reach the venous system at the jugular vein, resulting in a lymphatic stasis that starts in the neck region and continues to the rest of the body. From 2015 to 2020, a total of 5,730 ultrasound examinations were performed in mares from 43 different horse farms and embryo transfer farms when sexing pregnancies. In 12 pregnant mares, a s...
Vegas AR, Podico G, Canisso IF, Bollwein H, Fröhlich T, Bauersachs S, Almiñana C.During initial maternal recognition of pregnancy (MRP), the equine embryo displays a series of unique events characterized by rapid blastocyst expansion, secretion of a diverse array of molecules, and transuterine migration to interact with the uterine surface. Up to date, the intricate transcriptome and proteome changes of the embryo underlying these events have not been critically studied in horses. Thus, the objective of this study was to perform an integrative transcriptomic (including mRNA, miRNAs, and other small non-coding RNAs) and proteomic analysis of embryos collected from days 10 t...
Diel de Amorim M, Bramer SA, Rajamanickam GD, Klein C, Card C.Our objectives were to examine changes in endometrial and luteal gene expression during estrus, diestrus, pregnancy and treatments to induce luteolysis and putatively induce luteostasis. Groups were: Diestrus (DIEST), Estrus (ESTR), Pregnant (PREG), Oxytocin (OXY), Carbetocin (CARB), and Meclofenamic acid (MFA). Blood was obtained from day (D)12 to D15 for measurement of oxytocinase, also referred to as leucyl-cysteinyl aminopeptidase (LNPEP) and progesterone. Luteal biopsies were obtained on D12 and D15 and an endometrial biopsy on D15. Real-time RT-PCR was performed for the following genes: ...
Ramírez-Agámez L, Hernández-Avilés C, Varner DD, Love CC.Intracytoplasmic Sperm Injection (ICSI) using frozen/thawed sperm is a common procedure to obtain embryos from fertile or subfertile mares and stallions. Stallion-associated factors that impact the efficiency of ICSI have been studied less than those associated with the mare. Three experiments were conducted: Experiment 1: the effect of freezing extender composition and cryoprotectant; Experiment 2: the effect of sperm exposure to seminal plasma prior to freezing (ejaculated vs. epididymal sperm; two-freeze/thaw cycles each); and Experiment 3: the effect of sperm morphologic feature used for f...
Mimoun L, Steinman A, Kliachko Y, Tirosh-Levy S, Schvartz G, Blinder E, Baneth G, Mazuz ML.Equine Neospora infection has been linked to neurological disorders and infertility in horses. This study looked into the risk factors for infection and the exposure to Neospora spp. in horses. The study was performed in two independent populations in Israel. The first consisted of apparently healthy horses, and the second consisted of mares examined during pregnancy and after parturition. Sera samples collected from horses and mares were tested for Neospora exposure by the indirect fluorescent antibody test (IFAT). The study revealed seroprevalence of 24% in apparently healthy horses and 66.4...
Lanci A, Mariella J, Ellero N, Canisso IF, Dondi F, Castagnetti C.This study aimed to determine alpha-fetoprotein (AFP) concentrations in amniotic fluid, plasma of mares and respective foals: carrying normal pregnancies and delivering healthy foals (n = 20; Group 1); carrying apparently normal pregnancies and delivering sick foals (n = 15; Group 2); carrying high-risk pregnancies and delivering sick foals (n = 14; Group 3). High-risk pregnancy was defined by a history of premature udder development/lactation or increased of the combined thickness of the uterus and placenta, or vulvar discharge and/or mares' systemic illness. Sick foals were affected by...
Rudolf Vegas A, Hamdi M, Podico G, Bollwein H, Fröhlich T, Canisso IF, Bauersachs S, Almiñana C.In contrast to other domestic mammals, the embryo-derived signal(s) leading to maternal recognition of pregnancy (MRP) are still unknow in the mare. We hypothesize that these embryonic signals could be packed into uterine extracellular vesicles (uEVs), acting as multi-signal messengers between the conceptus and the maternal tract, and contributing to MRP. To unveil these signals, the RNA and protein cargos of uEVs isolated from uterine lavages collected from pregnant mares (P; day 10, 11, 12 and 13 after ovulation) and cyclic control mares (C; day 10 and 13 after ovulation) were analyzed. Our ...
Felix MR, Turner RM, Dobbie T, Hinrichs K.Methods for standard in vitro fertilization have been difficult to establish in the horse. We evaluated whether prolonged sperm pre-incubation would support subsequent fertilization. Fresh sperm were pre-incubated with penicillamine, hypotaurine, and epinephrine (PHE) for 22 h. Co-incubation of cumulus-oocyte complexes (COCs) for 6 h yielded 43% fertilization; culture of presumptive embryos yielded 21% blastocysts. Sperm incubated similarly, but without PHE, did not fertilize oocytes. Use of extended semen in the system yielded 54% blastocysts and was applied in subsequent experiments. Trans...
Hollinshead FK, Mehegan MK, Gunn A, Nett T, Bruemmer JE, Hanlon DW.The aim of this project was to test the hypothesis that progesterone concentration 5 days after ovulation did not differ between pregnant and nonpregnant Thoroughbred mares on stud farms located in the Waikato region of New Zealand. A prospective cohort study was performed involving five stud farms in the Waikato region of New Zealand during the 2018 breeding season. A total of 275 mares were enrolled in the study. Mares were served by 34 individual stallions. Blood samples were taken from each mare 5 days after ovulation (D0) and measured for progesterone concentration. Early pregnancy was co...
Gibson C, de Ruijter-Villani M, Stout TAE.In many species, the insulin-like growth factors (IGF1 and IGF2), their receptors and IGF binding proteins play important roles in preparing the endometrium for implantation, and regulating conceptus growth and development. To determine whether the IGF system may contribute to conceptus-maternal interaction during equine pre-implantation development, we evaluated mRNA expression for IGF system components in conceptuses, and endometrium recovered from pregnant and cycling mares, on days 7, 14, 21 and 28 after ovulation. We also investigated expression of IGF1, IGF2 and their receptors 6 and 11 ...
Diel de Amorim M, Bramer SA, Rajamanickam GD, Klein C, Card C.Our understanding of the temporal changes in endometrial and luteal gene transcripts related to the actions of oxytocin and prostaglandin during early equine pregnancy is incomplete. Additionally, the role of oxytocinase, also known as Leucyl-cystinyl aminopeptidase (LNPEP), during early pregnancy in mares has not been previously investigated. Luteal and endometrial biopsies were obtained on Day (D)8, D10, D12 and D15 post-ovulation in pregnant (PREG) and diestrus (DIEST) mares for real-time qPCR. Differences in endometrial gene expression occurred over time in: SLC2A4, SLC2A1, PTGES, OXTR and...
Ellero N, Lanci A, Baldassarro VA, Alastra G, Mariella J, Cescatti M, Giardino L, Castagnetti C.The importance of trophic factors, such as nerve growth factor (NGF), vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF) during the perinatal period, is now emerging. Through their functional activities of neurogenesis and angiogenesis, they play a key role in the final maturation of the nervous and vascular systems. The present study aims to: (i) evaluate the NGF and VEGF levels obtained at parturition from the mare, foal and umbilical cord vein plasma, as well as in amniotic fluid; (ii) evaluate NGF and VEGF content in the plasma of healthy foals during t...
Mouncey R, Arango-Sabogal JC, de Mestre A, Verheyen K.The study aimed to (1) describe the use of reproductive therapeutics; (2) estimate the incidence of disease and injury; and (3) describe non-reproductive medications administered during pregnancy in Thoroughbred broodmares. A prospective birth cohort was established on seven farms across the UK and Ireland. Details of dams' signalment, breeding history, reproductive management during the breeding season(s) and veterinary-attended episodes of illness or injury and medication usage during gestation were retrieved retrospectively for 275 pregnancies in 235 mares over two breeding seasons. Results...
Oquendo PS, Silva ESM, Oquendo FMG, Cuervo-Arango J, Beletti ME.The effect of three different hormonal protocols to prepare anestrous recipient mares on embryo survival was evaluated. The first group consisted of only progesterone administration (NE) 4 days before embryo transfer, while the recipients from the other two groups received a single administration of 2.5 mg of oestradiol benzoate (SE) 2 days earlier or 8 mg of oestradiol split in increasing doses for 5 consecutive days (LE) ending 3 days before progesterone treatment. The likelihood of recovering an embryo 2 days after transfer was 46.1% (6/13), 62.5% (5/8) and 85.7% (6/7) for recipie...
Stonehouse O, Stefanovski D, Bowman B, Sertich PL, Demchur J, Lewis GM, Turner RM, Turner RMO.Nocardioform placentitis (NP) has been associated with mid to late pregnancy loss in mares. To date, disease outbreaks have been described only in central Kentucky, although sporadic, isolated cases have been reported globally. This study describes a series of cases of NP that occurred in a sample population of 299 mares foaling in southeastern Pennsylvania and northeastern Maryland in 2020. These cases coincided with an outbreak of NP that occurred in Kentucky that same year. On farms that reported information on both normal and abnormal foalings, nocardioform organisms/DNA were isolated from...
Shen Y, Ren H, Davshilt T, Tian S, Wang X, Yi M, Ulaangerel T, Li B, Dugarjav M, Bou G.During equine early gestation, trophectoderm forms chorion tissue, which is composed of two parts that one is covering allantoin, called allantochorion (AC) and another is covering yolk sac, which here we call vitelline-chorion (VC). Given that little is known about the equine trophoblast-derived chorion differentiation at an early stage, we first compared the transcriptome of AC and VC of day 30 equine conceptus based on RNA-sequencing. As a result, we found that compared to VC, there are 484 DEGs, including 305 up- and 179 down-regulated genes in AC. GO and KEGG analysis indicated that up-re...
El-Sheikh Ali H, Scoggin K, Murase H, Norris J, Menarim B, Dini P, Ball B.The equine chorioallantois (CA) undergoes complex physical and biochemical changes during labor. However, the molecular mechanisms controlling these changes are still unclear. Therefore, the current study aimed to characterize the transcriptome of equine CA during spontaneous labor and compare it with that of normal preterm CA. Placental samples were collected postpartum from mares with normal term labor (TL group, n = 4) and from preterm not in labor mares (330 days GA; PTNL group, n = 4). Our study identified 4137 differentially expressed genes (1820 upregulated and 2317 downregulat...
Ellenberger C, Wilsher S, Allen WR, Hoffmann C, Kölling M, Bazer FW, Klug J, Schoon D, Schoon HA.Previous studies have shown that the equine uterus produces many progesterone-dependent proteins throughout gestation. In particular, uterocalin and uteroferrin are detectable using electrophoresis or blot analyses but information regarding the immunohistochemical placental distribution of these two proteins is rare and information regarding uteroglobin is still lacking. The aim of the present study was to co-immunolocalise these three secretory proteins in the mare's uterus throughout gestation in an effort to understand their functional role in the maintenance of pregnancy. Therefore, endome...
Maclellan LJ, Carnevale EM, Coutinho da Silva MA, Scoggin CF, Bruemmer JE, Squires EL.The objectives were to compare embryo development rates after transfer into inseminated recipients, vitrified thawed oocytes collected from super-stimulated versus non-stimulated mares. In vivo matured oocytes were collected by transvaginal, ultrasound guided follicular aspiration from super-stimulated and non-stimulated mares 24-26 h after administration of hCG. Oocytes were cultured for 2-4 h prior to vitrification. Cryoprotectants were loaded in three steps before oocytes were placed onto a 0.5-0.7 mm diameter nylon cryoloop and plunged directly into liquid nitrogen. Oocytes were thawed and...
Hicks BA, Etter SJ, Carnahan KG, Joyce MM, Assiri AA, Carling SJ, Kodali K, Johnson GA, Hansen TR, Mirando MA, Woods GL, Vanderwall DK, Ott TL.Pregnancy and interferon-tau (IFN tau) upregulate uterine Mx gene expression in ewes; however, the only known role for Mx is in the immune response to viral infection. We hypothesize that Mx functions as a conceptus-induced component of the anti-luteolytic mechanism and/or regulator of endometrial secretion or uterine remodeling during early pregnancy. This study was conducted to determine the effects of early pregnancy on uterine Mx expression in domestic farm species with varied mechanisms of pregnancy recognition. Endometrium from cows, gilts, and mares was collected during the first 20 d o...
Sieme H, Martinsson G, Rauterberg H, Walter K, Aurich C, Petzoldt R, Klug E.The objective of this research was to improve the techniques in processing chilled and frozen-thawed horse semen. In a preliminary experiment (Exp. I), different techniques for sperm selection and preparation [Swim-up, Glass wool (GW) filtration, Glass wool Sephadex (GWS) filtration; Percoll] were tested for their suitability for equine spermatozoa and results were compared with the routine procedure by dilution (Exp. I). In the main experiment (Exp. II), two sperm preparation techniques (GWS, Leucosorb) refering to the results of Exp. I and a previous study of our group (Pferdcheilkunde 1996 ...
Wood PL, Ball BA, Scoggin K, Troedsson MH, Squires EL.Amniotic fluid is essential for the growth and maturation of the fetus prior to parturition. While our knowledge of human amniotic fluid is extensive, current data for equine amniotic fluid is limited. We therefore undertook a detailed lipidomics analysis of equine amniotic fluid. Using a non-targeted high-resolution mass spectrometric lipidomics analysis of equine amniotic fluid, we were able to characterize a diverse array of individual lipids. This non-biased analytical approach detected, for the first time, the presence of (O-acyl)-ω-hydroxy-fatty acids (OAHFA) with up to 52 carbon chain ...
Kirkpatrick JF, Turner A.Contraceptive management of publicly valued wildlife species requires safeguards to ensure that these populations are preserved in a healthy state. In addition, reversibility of contraceptive effects and safety in pregnant animals are major concerns. A population of wild horses has been immunized against porcine zona pellucida (PZP) over a 12 year period on Assateague Island National Seashore, MD (ASIS). Mares initially received one or two 65 microg inoculations and once a year 65 microg booster inoculations, all delivered by dart. All young mares aged > 2 years were treated with PZP for 3 ...
Flood PF, Betteridge KJ, Diocee MS.The 23 embryos were obtained by flushing the reproductive tract. Though the general cytology was observed, most attention was given to the formation of the embryonic capsule. It first appeared as a thin uniform layer on the inner surface of the zona pellucida of embryos recovered from the uterus on Day 6. By Day 8 the capsule was about 1 micron thick and the zona pellucida had been shed. In fixed embryos of 11 days and over the capsule was 3 microns thick and had a finely stippled but otherwise homogeneous appearance.
de Ruijter-Villani M, van Boxtel PR, Stout TA.Uterine-derived growth factors and cytokines play essential roles in regulating preimplantation conceptus development. In several species, fibroblast growth factor-2 (FGF2) promotes embryogenesis, trophoblast cell migration, and adhesion. This study investigated mRNA expression for FGF2, its receptors (FGFR1-4), the activating factor FGF binding protein (FGF-BP) in equine endometrium and trophectoderm during early pregnancy and the estrous cycle, and localized FGF2 protein in both endometrium and conceptus tissues. FGF2, FGFRs1-4, and FGFBP mRNAs were expressed in endometrium throughout the es...
Rizzo M, du Preez N, Ducheyne KD, Deelen C, Beitsma MM, Stout TAE, de Ruijter-Villani M.Aneuploidy of meiotic origin is a major contributor to age-related subfertility and an increased risk of miscarriage in women. Although age-related aneuploidy has been studied in rodents, the mare may be a more appropriate animal model to study reproductive aging. Similar to women, aged mares show reduced fertility and an increased incidence of early pregnancy loss; however, it is not known whether aging predisposes to aneuploidy in equine oocytes. We evaluated the effect of advanced mare age on (1) gene expression for cohesin components, (2) incidence of aneuploidy and (3) chromosome centrome...
Klewitz J, Struebing C, Rohn K, Goergens A, Martinsson G, Orgies F, Probst J, Hollinshead F, Bollwein H, Sieme H.Color Doppler sonography has become routine for the evaluation of high-risk pregnancies in human medicine. Previous studies documenting uterine blood flow parameters in the pregnant mare have found a decrease in peripheral blood flow resistance in the first pregnancy weeks and an increase in uterine blood flow, especially in the last trimester of pregnancy. However, these studies involved only a small number of mares. No naturally occurring pregnancy abnormalities occurred that would allow blood flow changes to be retrospectively examined and analyzed. The objective of the present study was to...
Love CC, Kenney RM.The relationship between fertility and susceptibility of sperm DNA to denaturation was determined in a group of 84 actively breeding, clinically fertile stallions. Susceptibility of DNA to denaturation was determined using the sperm chromatin structure assay (SCSA). The SCSA measures, mean of alpha-t (mean alpha t), standard deviation of alpha-t (SD alpha t), and the COMP of alpha-t (cells outside the main population)] were significantly correlated with the percentage seasonal pregnancy rate (SPR; mean alpha t, r = -0.24, P < or = 0.05; % COMP alpha t, r = -0.27, P < or = 0.05); percentage pre...
Tallmadge RL, McLaughlin K, Secor E, Ruano D, Matychak MB, Flaminio MJ.Many features of the equine immune system develop during fetal life, yet the naïve or immature immune state of the neonate renders the foal uniquely susceptible to particular pathogens. RT-PCR and immunohistochemical experiments investigated the progressive expression of developmental B cell markers and immunoglobulins in lymphoid tissues from equine fetus, pre-suckle neonate, foal, and adult horses. Serum IgM, IgG isotype, and IgA concentrations were also quantified in pre-suckle foals and adult horses. The expression of essential B cell genes suggests active development and gene recombinati...
Aleksic D, Blaschke L, Mißbach S, Hänske J, Weiß W, Handler J, Zimmermann W, Cabrera-Sharp V, Read JE, de Mestre AM, O'Riordan R, Moore T....Pregnancy-specific glycoproteins (PSGs) are members of the carcinoembryonic antigen cell adhesion molecule (CEACAM) family that are secreted by trophoblast cells. PSGs may modulate immune, angiogenic and platelet responses during pregnancy. Until now, PSGs are only found in species that have a highly invasive (hemochorial) placentation including humans, mice and rats. Surprisingly, analyzing the CEACAM gene family of the horse, which has a non-invasive epitheliochorial placenta, with the exception of the transient endometrial cups, we identified equine CEACAM family members that seem to be rel...
Kikuchi M, Nakano Y, Nambo Y, Haneda S, Matsui M, Miyake Y, Macleod JN, Nagaoka K, Imakawa K.A factor responsible for progression to pregnancy establishment in the mare has not been definitively characterized. To identify factors possibly involved in the establishment of equine pregnancy, the endometrium was collected from day 13 (day 0=day of ovulation) cyclic and day 13, 19 and 25 pregnant animals. From initial subtractive hybridization studies, a calcium regulating factor, Stanniocalcin-1 (STC1) mRNA, was found as a candidate molecule expressed uniquely in the pregnant endometrium. Endometrial expression of STC1 mRNA was noted on day 19 and was markedly increased in the day 25 grav...
Hemberg E, Lundeheim N, Einarsson S.During 1997-2001, a total of 430 Thoroughbred mares were mated by one of the two Thoroughbred stallions on a well-managed stud farm in the central part of Sweden. On arrival, a thorough gynaecological examination of all mares was performed. An early pregnancy examination was performed on days 14 and 15 after ovulation. The overall conception rates for the two stallions were 92.2 and 88.8%, and the corresponding live foal rates were 82.6 and 75.2%, respectively. The mean number of served oestrous cycles was 1.60 per mare per conception and 1.86 per live foal. The first and second cycle concepti...
Pohlin F, Brabender K, Fluch G, Stalder G, Petit T, Walzer C. Ecosystems with seasonal fluctuations in climate and food availability present physiological challenges to resident mammals and may cause "stress." The two predominant physiological responses to stressors are (1) the activation of the hypothalamic-pituitary-adrenal axis and (2) the modulation of the autonomic nervous system. To date, the primary indicator for "stress" in wildlife- and zoo animal research are glucocorticoid levels. By measuring the autonomic regulation of cardiac activity, particularly the vagal tone, heart rate variability (HRV) is presently emerging as a suitable indicator o...
Hinrichs K, Choi YH, Varner DD, Hartman DL.We evaluated the effect of different activation treatments on the production of blastocysts and foals by nuclear transfer. Donor cells were prepared using roscovitine treatment, which has previously been associated with increased production of viable offspring. All activation treatments were followed by culture in 6-dimethylaminopurine (6-DMAP) for 4 h. In experiment 1, blastocyst production after activation by injection of sperm extract followed by treatment with ionomycin was significantly higher than that for activation with a serial treatment of ionomycin, 6-DMAP, and ionomycin (12.5 vs 2....
Noronha LE, Huggler KE, de Mestre AM, Miller DC, Antczak DF.To identify equine orthologs of major NK cell marker genes and utilize them to determine whether NK cells are present among the dense infiltration of lymphocytes that surround the endometrial cup structures of the horse placenta during early pregnancy. Methods: PCR primers were developed to detect the equine orthologs of NKP46, CD16, CD56, and CD94; gene expression was detected in RNA isolated from lymphocytes using standard 2-step reverse transcriptase (RT) PCR and products were cloned and sequenced. Absolute real-time RT-PCR was used to quantitate gene expression in total, CD3+, and CD3- per...
Squires E.Numerous reproductive technologies have been developed in the past several decades, which have dramatically changed the way mares are bred. This review will focus on embryo recovery and transfer, cooled-shipped embryos, embryo freezing, oocyte freezing, oocyte collection and transfer, intracytoplasmic sperm injection (ICSI), and sexed semen. Embryo transfer procedures have been constant for many years and the costs have not changed. The major change has been the ability to store embryos at 5 C for 12-24 hours and transport them to recipient stations. Embryo freezing has become more common us...
Guasti PN, Souza FF, Scott C, Papa PM, Camargo LS, Schmith RA, Monteiro GA, Hartwig FP, Papa FO.During ejaculation, a large amount of seminal plasma proteins interact with the sperm membrane, leading to a series of biochemical and structural changes implicated in sperm function and gamete interaction. However, the roles of the majority of these proteins remain unknown. This study aimed to investigate the proteome and functionality of the major equine proteins of seminal plasma and the sperm membrane. Seminal plasma and enriched-membrane proteins (150 μg) were separated by two-dimensional gel electrophoresis, and the respective maps were analyzed. Protein identification was performed by...
Elliott C, Morton J, Chopin J.Foaling data from 348 Thoroughbred foals born on a commercial stud were analysed to investigate interrelationships among mare age, parity, gestation length, foal sex, placental weight, and foal birth weight. Placental weight was positively correlated with foal birth weight up to a threshold of 6.5 kg; above this, placental weight was not significantly associated with foal birth weight. Placental weight was assessed, including the amniotic membranes and umbilical cord as well as the allantochorion. Using path analysis, parity was positively associated with foal birth weight both directly and th...
Kouba JM, Burns TA, Webel SK.The effects of dietary marine-derived n-3 fatty acids (FA) on mare milk and mare and foal plasma FA, postpartum ovarian follicular growth and prostaglandin concentrations were evaluated. Sixty days prior to expected foaling dates, mares were assigned to one of three diets: corn oil (CORN, n = 6), docosahexaenoic acid (DHA) diet (D; 12.64 g/d, n = 7), or eicosapentaenoic acid (EPA) and DHA (ED; 8.84 g EPA, 10.43 g DHA/d, n = 7). Milk and plasma were collected for FA analysis. Follicular data were recorded through the first postpartum ovulation. Post-ovulation serial blood samp...
Squires EL, Carnevale EM, McCue PM, Bruemmer JE.Recent studies demonstrated that zwitterionic buffers could be used for satisfactory storage of equine embryos at 5 degrees C. The success of freezing embryos is dependent upon size and stage of development. Morulae and blastocysts <300 microm can be slowly cooled or vitrified with acceptable pregnancy rates after transfer. The majority of equine embryos are collected from single ovulating mares, as there is no commercially available product for superovulation in equine. However, pituitary extract, rich in FSH, can be used to increase embryo recovery three- to four-fold. Similar to human medic...
Ellinger I.Active placental transport of maternal serum calcium (Ca(2+)) to the offspring is pivotal for proper development of the fetal skeleton as well as various organ systems. Moreover, extracellular Ca(2+) levels impact on distinct processes in mammalian reproduction. The calcium-sensing receptor (CaSR) translates changes in extracellular Ca(2+)-concentrations into cellular reactions. This review summarizes current knowledge on the expression of CaSR and its putative functions in reproductive organs. CaSR was detected in placental cells mediating materno-fetal Ca(2+)-transport such as the murine int...
Ealy AD, Eroh ML, Sharp DC.The equine embryo must signal its presence to the uterus for pregnancy to continue to term. Mobility of the conceptus throughout the uterus is crucial for its survival, and this action presumably permits the conceptus to transmit its antiluteolytic signal to the endometrium. Studies were completed to establish whether this unidentified antiluteolytic signal targets prostaglandin G/H synthase 2 (PGHS2), a rate limiting enzyme in converting arachidonic acid to prostaglandins (PGs). In the first study, quantitative RT-PCR was used to determine the relative abundance of PGHS2 mRNA in endometrium d...
Loomis PR.Recent acceptance of frozen semen as a method to produce registered foals by two of the worlds largest breed associations, the American Quarter Horse and American Paint Horse, has stimulated new interest in frozen semen technology. This review will: (a) attempt to identify the major impediments to the development of the frozen semen industry, (b) suggest alternative methods for marketing and application of frozen semen, and (c) present the results of a recent study in our laboratory. The objective of which was to compare pregnancy rates of insemination with cooled and frozen semen. Major imped...
Kirkpatrick JF, Liu IM, Turner JW, Naugle R, Keiper R.Ten feral mares free-roaming in Maryland, USA, were inoculated with porcine zonae pellucidae (PZP) protein before the breeding season for three consecutive years (1988-90). Ovarian function was monitored for 51 days during the peak of the breeding season after the third annual PZP inoculation, in seven of these mares and in four untreated control mares, by means of urinary oestrone conjugates and nonspecific progesterone metabolites. None of the ten inoculated mares became pregnant in 1990, compared with 55% of 20 control mares, which included two of the four monitored for ovarian function. Th...
