Fetal health in horses encompasses the study of the development and well-being of the equine fetus during gestation. This area of research focuses on understanding the physiological processes that occur from conception to birth, including fetal growth, placental function, and maternal-fetal interactions. Factors influencing fetal health can include genetics, nutrition, environmental conditions, and maternal health status. Monitoring fetal health is important for identifying potential complications such as developmental abnormalities or pregnancy loss. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, assessment methods, and implications of fetal health in equine reproduction.
Conley AJ, Ball BA.Historically, studies on the endocrinology of pregnancy and parturition in horses have made major contributions of relevance to mammals in general. Recent use of liquid chromatography mass spectrometry, measuring multiple steroid hormones simultaneously in blood, foetal and placental tissues throughout normal gestation, and in mares with experimentally induced placentitis, has advanced our current understanding of many of the unusual strategies seen during gestation and at foaling. This includes the stimulation of luteal steroidogeneisis by equine chorionic gonadotropin (eCG) from the endometr...
Ellerbrock RE, Canisso IF, Roady PJ, Litsky A, Durgam S, Podico G, Li Z, Lima FS.A recent study demonstrated that enrofloxacin and ciprofloxacin cross the equine placenta without causing gross cartilage or tendon lesions in the 9-month fetus; however, long-term effects of in utero fluoroquinolone exposure remain unknown. Objective: To assess effects of fetal exposure to enrofloxacin on the resulting foal's cartilage and tendon strength. Methods: Healthy mares at 280 days' gestation were allocated into four groups: untreated (n = 5), therapeutic treatment (7.5 mg/kg enrofloxacin, PO × 14 days, n = 6), supratherapeutic treatment (15 mg/kg, PO × 14 days, n = ...
Canisso IF, Loux S, Scoggin KE, Squires EL, Troedsson MH, Ball BA.Characterisation of fetal fluids in healthy and disease states of pregnant mares can help to unravel the pathophysiology and to identify putative markers of disease. Thus, this study aimed to compare the protein composition of: (1) amniotic and allantoic fluids of healthy mares obtained immediately after euthanasia and (2) allantoic fluid harvested via centesis before and after experimental induction of placentitis via transcervical inoculation of Streptococcus equi ssp zooepidemicus in healthy mares. Fetal fluids were analysed with a high-throughput proteomic technique after in-gel digestion....
Mitchell ARM, Delvescovo B, Tse M, Crouch EE, Cheong SH, Castillo JM, Felippe MJB, Ainsworth DM, de Amorim MD.A 6-year-old Standardbred mare was presented at 339 days of gestation for investigation of abnormal abdominal distension and ventral edema. Transrectal palpation and ultrasound examination revealed the uterus to be enlarged with an excessive volume of fetal fluid, characteristic of hydrops. Gradual transcervical drainage of 55 L of allantoic fluid over 45 minutes, with concurrent intravenous fluid therapy followed by assisted vaginal delivery, resulted in the birth of a live foal with long-term survival. The birth and long-term survival of a foal from a mare with hydrallantois at term has not ...
Pessôa LVF, Pires PRL, Del Collado M, Pieri NCG, Recchia K, Souza AF, Perecin F, da Silveira JC, de Andrade AFC, Ambrosio CE, Bressan FF....Pluripotent stem cells are believed to have greater clinical potential than mesenchymal stem cells due to their ability to differentiate into almost any cell type of an organism, and since 2006, the generation of patient-specific induced pluripotent stem cells (iPSCs) has become possible in multiple species. Objective: We hypothesize that different cell types respond differently to the reprogramming process; thus, the goals of this study were to isolate and characterize equine adult and fetal cells and induce these cells to pluripotency for future regenerative and translational purposes. Metho...
Legacki EL, Bal BA, Corbin CJ, Loux SC, Scoggin KE, Stanley SD, Conley AJ.The authors apologize for errors in Figure 6 of their article published in the October 2017 issue of Reproduction (vol 154 iss 4 pp 445–454). The authors explain that the addition of data (Figure 6) on steroid concentrations in the chorioallantois to their manuscript on fetal adrenal and fetal gonadal steroids during development of the equine fetus was made in response to reviewer comments. However, in compiling, summarizing and graphing the data, the wrong units were used in the final figure. The manuscript as published represents the data in Figure 6 as “ng/g”, when in fact they are ...
Nagel C, Aurich C, Aurich J.This review summarizes current knowledge on stress-like responses in parturient animals and their role for the onset and fine-tuning of parturition. The antepartum maternal cortisol increase is part of the endocrine changes that initiate parturition but a further increase in cortisol release during labor indicates a stress response. During the last minutes of delivery, sinus arrhythmias occur in 80% of foaling mares and 60% of calving cows. Expulsion of the neonate is thus characterized by parasympathetic dominance. In late-pregnant cows transported by road, cortisol concentrations increased b...
Aurich J, Köhne M, Wulf M, Nagel C, Beythien E, Gautier C, Zentek J, Aurich C.The importance of the amino acid L-arginine (ARG) for conceptus growth and litter size has been demonstrated in various species. L-arginine is part of embryo-derived polyamines, a substrate for nitric oxide synthase and stimulates protein synthesis by the embryo. In the present study, we have investigated whether dietary L-arginine supplementation stimulates early conceptus growth in mares. Warmblood mares with singleton pregnancies received either an arginine-supplemented diet (approximately 0.0125% of body weight, n = 12) or a control diet (n = 11) from days 15 to 45 after ovulation. Dia...
Mebarki M, Kaidi R, Azizi A, Basbaci M.Ultrasonographic fetal sexing is of utmost economic importance for horse breeders. Relatively, a few studies have been conducted to determine fetal sex in mare using transrectal Doppler ultrasound. This study aimed to compare two sexing techniques, two-dimensional (2D) mode and color Doppler ultrasonography. Methods: The study was conducted on 39 mares under field conditions. Examinations were performed using the ultrasonic model device (Medison SonoAce Pico, South Korea), equipped with real-time 3-7 MHz convex multifrequency transducer. Fetal sex diagnosis was carried out in two periods of pr...
Cheong SH, Castillo Herrera JM, Dockweiler JC, Donnelly CG, Sones JL, Ellerbrock RE, Lawlis SM, Gilbert RO, Diel de Amorim M.Augmentation of parturition can be used to advance labor in mares to occur at a time when personnel is available to assist if necessary. We performed a retrospective study to determine the efficacy and safety of augmentation to manage foalings. Augmentation was performed with 3 IU oxytocin i.v. when mammary calcium concentrations were ≥250 ppm, mammary secretion pH ≤ 6.5, and the mare showed impending signs of parturition. Augmented parturitions (n = 19) were compared with three different control groups. The three control groups were: 1) Time Match control (n = 37) which were...
Melchert M, Aurich C, Aurich J, Gautier C, Nagel C.Mares usually give birth when they perceive their environment as safe and therefore disturbance at foaling may inhibit labor. In this study, foaling mares were transferred to an unfamiliar environment at rupture of the allantochorion (stress, n = 6) or were left undisturbed (control, n = 5). The progress of foaling, heart rate, heart rate variability (HRV) and plasma catecholamine, oxytocin and cortisol concentration were determined. In stressed mares, time from rupture of the allantochorion to appearance of the fetal feet (5.3 ± 1.1 vs. 1.6 ± 0.4 min) and total length of f...
Rigoglio NN, Smith OE, Matias GSS, Miglino MA, Smith LC.Because of the growing importance of horses in leisure and several sports, somatic cell nuclear transfer (SCNT) is being used more frequently for cloning animals for performance and reproductive purposes. However, because of the need to perforate the zona pellucida during microsurgical reconstruction of the oocyte, it is possible that SCNT-derived embryos undergo premature hatching, resulting in embryo bisection and twinning. Therefore, because equine twin pregnancies often lead to abnormal embryo development and pregnancy failure, we performed a detailed comparative assessment of equine twin ...
Divers TJ, Chang YF, Irby NL, Smith JL, Carter CN.North American horses are commonly exposed to Leptospira organisms. Leptospira Bratislava is the most common infecting serovar but this serovar has not been confirmed to cause clinical disease in North American horses. Leptospira Pomona type kennewicki is responsible for most of the clinical diseases (leptospirosis) in North American horses. Leptospirosis is most commonly associated with diseases of the placenta and fetus, the kidneys and the eyes in horses. In-utero infections in pregnant mares may result in abortion, neonatal illness or birth of an antibody positive healthy foal. Acute renal...
Ellerbrock RE, Canisso IF, Roady PJ, Rothrock LT, Zhong L, Wilkins P, Dirikolu L, Lima FS, Honoroto J.In selective cases, enrofloxacin may be an alternative antibacterial agent to treat unresponsive infections in pregnant mares. Supratherapeutic doses of enrofloxacin are toxic to adult horses and also to newborn foals, however, it is unknown if enrofloxacin crosses the equine placenta or if it is toxic to the fetus. Objective: To assess the diffusion of enrofloxacin and its metabolite to fetal fluids and its effects on fetal cartilage when administered to pregnant mares. Methods: In vivo and terminal controlled experiment. Methods: Healthy mares at 260 days of gestation were allocated into thr...
Rigoglio NN, Matias GSS, Miglino MA, Mess AM, Jacob JCF, Smith LC.Hybrids between species are often infertile and extremely rare among mammals. Mules, i.e. crossing between the horse and the donkey, on the other hand are very common in agricultural and leisure practices due to their enhanced post-natal physical characteristics that is believed to occur for outbreeding or hybrid vigor. Since no reports are availableon the effects of hybrid vigor during early development, this study focused on characterizing the intrauterine development of mule conceptuses during critical embryo-to-fetus transition period. Nine embryos and fetuses of early gestation, obtained ...
Becsek A, Tzanidakis N, Blanco M, Bollwein H.The aim of this study was to investigate if transrectal three-dimensional (3D) ultrasound is a reliable technique to measure equine fetal volume (FV) during early gestation in mares. In total 149 warmblood mares were examined once transrectally on days 45 ± 1 of pregnancy with a portable 3D ultrasound device (Voluson i, GE Healthcare, Zipf, Austria). The following measurements were performed: Two-dimensional (2D) and 3D crown-rump length (CRL), FV using Virtual Organ Computer-aided AnaLysis (VOCAL™) software with rotational angles of 6° and 30°. To analyze intra- and inter-observer re...
Vincze B, Baska F, Papp M, Szenci O.Prepartum fetal surveillance techniques have been widely used in both human and veterinary obstetrics, although these tests differ in their sensitivity for the assessment of fetal well-being. In equine reproduction, the 'gold standard' examination technique is the equine biophysical profile (EBP) described by Virginia Reef in 1995. Although this fetal assessment has many benefits, its accuracy, sensitivity and specificity have not been evaluated so far. In this study, 129 late-term pregnant mares were scanned twice in their last month of gestation using two different protocols (the EBP and a n...
Vincze B, Solymosi N, Debnár V, Kútvölgyi G, Krikó E, Wölfling A, Szenci O.Alpha-fetoprotein (AFP) is best known in human obstetrics for its association with fetal anomalies recognized in the 1970s. Although this fetal protein had been shown to be present in the sera of many mammalian species, its possible diagnostic role in the detection of abnormalities was evaluated only later, when a research laboratory published variable levels of AFP in different groups of mares with pregnancy problems (twins, conception failure, placentitis, embryonic loss), and subsequently differences were demonstrated in its serum levels between aborted and healthy mares. In this study, per...
Wynn MAA, Ball BA, May J, Esteller-Vico A, Canisso I, Squires E, Troedsson M.The objectives of this study were to compare via liquid chromatography-tandem mass spectrometry (LC-MS/MS) progesterone (P4), 5α-dihydroprogesterone (DHP), allopregnanolone, 3β-hydroxy-5α-pregnan-20-one (3β5P), 20α-hydroxy-5α-pregnan-3-one (20α5P), 5α-pregnan-3β,20α-diol (βα-diol), and 5α-pregnan-3β,20β-diol (ββ-diol) concentrations in plasma of mares with experimentally-induced, ascending placentitis compared to gestationally age-matched control mares. Placentitis was induced via intracervical inoculation of Streptococcus equi spp. zooepidemicus between 260 and 280 days of ge...
Vera L, Decloedt A, Van Steenkiste G, De Clercq D, Govaere J, van Loon G.A 15-year-old Warmblood mare, at 8 months of gestation, was presented to the Ghent University Faculty of Veterinary Medicine for evaluation of suspected stage one labor. Transrectal ultrasonography revealed no clear signs of placentitis or stage one labor. The combined thickness of uterus and placenta was 11 mm and the cervix was closed. Twin pregnancy was suspected by transabdominal ultrasonography but could not be confirmed with certainty. An electrocardiogram (ECG) was recorded from the mare's abdominal wall to register a fetal ECG. To confirm twin pregnancy, registration of both fetal ECG...
Van de Velde M, Roels K, Ververs C, Gerits I, Govaere J.In recent years, the interest in equine foetal gender determination (FGD) during gestation increased remarkably. Ultrasonographic FGD can be performed in two different periods during gestation. The earliest examination can take place at a gestational age of 60-70 days, whereby the genital tubercle is used to differentiate between male and female foeti. The time window of the second approach is wider (120-210 days), and there are more characteristics to take into consideration. In this article, the feasibility and accuracy of ultrasonographic FGD in mid- to late gestation are evaluated. One h...
Robles M, Peugnet P, Dubois C, Piumi F, Jouneau L, Bouchez O, Aubrière MC, Dahirel M, Aioun J, Wimel L, Couturier-Tarrade A, Chavatte-Palmer P.Feeding pregnant broodmares with cereal concentrates has been shown to increase maternal insulin resistance and affect foal metabolism in the short and long-term. These effects are likely to be mediated by the placenta. Here, we investigated feto-placental biometry and placental structure and function at term in mares fed with or without cereals concentrates. From 7 months of gestation, 22 multiparous mares were fed forage only (group F (n = 12)) or received forage and cracked barley (group B (n = 10)) until foaling. Foals and placentas were weighed and placental samples were collected...
Diel de Amorim M, Chenier TS, Card C, Back B, McClure JT, Hanna P.Hydropsical conditions are exceedingly rare in the horse. However, when they occur, they are true emergencies due to the severe enlargement of the pregnant uterus, which can result in clinical signs, such as an enlarged round abdomen, dyspnea, reluctance to walk, and colic, and may lead to the development of abdominal wall disease. The pathogenesis of hydropsical conditions is not fully elucidated, but they have been associated with placentitis and fetal abnormalities. This report describes six cases of hydropsical conditions in mares with or without concurrent abdominal wall disease. Five out...
Ewert M, Lüders I, Böröcz J, Uphaus H, Distl O, Sieme H.The aim of the present study was to analyze the effects of stallion and mare, their ages, and maternal lineage on the gestation length (GL) in Thoroughbreds. In addition, additive genetic effects of the dam, stallion and fetus were analyzed. Data were taken from 1993 through 2009, and included 16,226 pregnancies from 5959 Th oroughbred mares mated with 290 different stallions. All analyses were performed using linear mixed models. The GL ranged from 306 to 390 days, with a mean length of 347.0 ± 14.4 days. Mating of mares with stallions aged 17 years and older resulted in a significantly ...
Wynn MAA, Ball BA, Legacki E, Conley A, Loux S, May J, Esteller-Vico A, Stanley S, Scoggin K, Squires E, Troedsson M.In the latter half of gestation in the mare, progesterone concentrations decline to near undetectable levels while other 5α-reduced pregnanes are elevated. Of these, 5α-dihydroprogesterone and allopregnanolone have been reported to have important roles in either pregnancy maintenance or fetal quiescence. During this time, the placenta is necessary for pregnane metabolism, with the enzyme 5α-reductase being required for the conversion of progesterone to 5α-dihydroprogesterone. The objectives of this study were to assess the effects of a 5α-reductase inhibitor, dutasteride on pregnane metab...
Clothier J, Hinch G, Brown W, Small A.Clear definitions of 'normal' equine gestation length (GL) are elusive, with GL being subject to a considerable number of internal and external variables that have confounded interpretation and estimation of GL for over 50 years. Consequently, the mean GL of 340 days first established by Rossdale in 1967 for Thoroughbred horses in northern Europe continues to be the benchmark value referenced by veterinarians, breeders and researchers worldwide. Application of a 95% confidence limit to reported GL range values indicates a possible connection between geographic location and GL. Improved kno...
Robles M, Peugnet PM, Valentino SA, Dubois C, Dahirel M, Aubrière MC, Reigner F, Serteyn D, Wimel L, Tarrade A, Chavatte-Palmer P.Ponies and sometimes draft horses are often used as experimental models for horses although size and metabolic parameters are known to vary between horse breeds. So far, there is little information about differences of placental structure and no information about differences of placental function between breeds. The aim of this study was to investigate differences in placental size, structure and function at birth in relation to foal size and weight in ponies, Saddlebred and draft horses. Pony, Saddlebred and draft horse pregnancies were obtained by artificial insemination over 2 successive br...
Kikuchi K, Sasaki K, Akizawa H, Tsukahara H, Bai H, Takahashi M, Nambo Y, Hata H, Kawahara M.Insulin-like growth factor 2 (IGF2) is responsible for a broad range of physiological processes during fetal development and adulthood, but genomic analyses of IGF2 containing the 5'- and 3'-untranslated regions (UTRs) in equines have been limited. In this study, we characterized the IGF2 mRNA containing the UTRs, and determined its expression pattern in the fetal tissues of horses. The complete equine IGF2 mRNA sequence harboring another exon approximately 2.8 kb upstream from the canonical transcription start site was identified as a new transcript variant. As this upstream exon did not cont...
Raeside JI.The role of steroids in human medicine is well recognized, but the major contributions made by the large domestic animals as a source of material in the discovery, isolation, and determination of the structure of the steroid hormones is less well appreciated. After a brief reminder of the early efforts to obtain a reliable source of steroids for clinical use, the narrative here is to outline one example where success was ultimately achieved for estrogen replacement therapy. Whereas knowledge of the high concentrations of estrogens in urine of pregnant women and mares dates from the late 1920s,...
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 ...
Tait AD, Santikarn S, Allen WR.The 5,7-dienes, 3 beta-hydroxy-5,7-pregnadien-20-one and 3 beta-hydroxy-5,7-androstadien-17-one were extracted from fetal horse gonads and purified by solvent partition, thin-layer chromatography and high performance liquid chromatography. The isolated steroids were identified by comparison with the synthetic steroids using ultraviolet and mass spectroscopy and by gas chromatography-mass spectroscopy. The identification of these compounds as endogenous steroids, together with the data on their biosynthesis reported previously, support the proposal that in the fetal horse gonad there is a 5,7-d...
Forhead AJ, Ousey JC, Allen WR, Fowden AL.This study examined the effects of intrauterine growth on insulin secretion and resistance in newborn foals. Embryo transfer between small pony and large Thoroughbred mares was used to produce four groups of foals with different birth weights (pony in pony n=7; pony in Thoroughbred n=7; Thoroughbred in Thoroughbred n=8; Thoroughbred in pony n=8). On day 2 after birth, glucose (0.5 g/kg) was administered intravenously to the foal and blood samples were taken for 2 h to determine plasma glucose and insulin concentrations. On day 3, insulin sensitivity was assessed by giving insulin (0.75 U/kg i....
Haneda S, Nagaoka K, Nambo Y, Kikuchi M, Nakano Y, Li J, Matsui M, Miyake YI, Imakawa K.From previous cDNA subtraction studies analyzing gene expression in equine endometrium, high lipocalin 2 (LCN2) mRNA expression was found in the gravid endometrium. In the uterus, LCN2 may transport hydrophobic molecules and siderophores with iron, or may form a complex with another protein, however, the expression of uterine LCN2 beyond day 20 of equine pregnancy and its receptor has not been characterized. To study the expression and potential roles of uterine LCN2 from pre-implantation to mid-gestation period, stage-specific endometrial samples were obtained from day 13 (day 0 = ovulation) ...
Tallmadge RL, Tseng CT, Felippe MJ.To further studies of neonatal immune responses to pathogens and vaccination, we investigated the dynamics of B lymphocyte development and immunoglobulin (Ig) gene diversity. Previously we demonstrated that equine fetal Ig VDJ sequences exhibit combinatorial and junctional diversity levels comparable to those of adult Ig VDJ sequences. Herein, RACE clones from fetal, neonatal, foal, and adult lymphoid tissue were assessed for Ig lambda light chain combinatorial, junctional, and sequence diversity. Remarkably, more lambda variable genes (IGLV) were used during fetal life than later stages and I...
Tallmadge RL, Tseng CT, King RA, Felippe MJ.Humoral immunity is a critical component of the immune system that is established during fetal life and expands upon exposure to pathogens. The extensive humoral immune response repertoire is generated in large part via immunoglobulin (Ig) heavy chain variable region diversity. The horse is a useful model to study the development of humoral diversity because the placenta does not transfer maternal antibodies; therefore, Igs detected in the fetus and pre-suckle neonate were generated in utero. The goal of this study was to compare the equine fetal Ig VDJ repertoire to that of neonatal, foal, an...
Peugnet P, Wimel L, Duchamp G, Sandersen C, Camous S, Guillaume D, Dahirel M, Dubois C, Jouneau L, Reigner F, Berthelot V, Chaffaux S, Tarrade A....In equids, placentation is diffuse and nutrient supply to the fetus is determined by uterine size. This correlates with maternal size and affects intra-uterine development and subsequent post-natal growth, as well as insulin sensitivity in the newborn. Long-term effects remain to be described. In this study, fetal growth was enhanced or restricted through ET using pony (P), saddlebred (S) and draft (D) horses. Control P-P (n = 21) and S-S (n = 28) pregnancies were obtained by AI. Enhanced and restricted pregnancies were obtained by transferring P or S embryos into D mares (P-D, n =...
Allen WR, Wilsher S, Tiplady C, Butterfield RM.The growth parameters exhibited by seven Thoroughbred (Tb) foals that had experienced a 'restricted' in utero existence following transfer as embryos to the uteri of smaller Pony (P) mares (Tb-in-P) and, conversely, six P foals that experienced a 'luxurious' in utero existence after transfer to larger Tb mares (P-in-Tb), were compared from birth to 3 years of age with those exhibited by six normal Tb-in-Tb and six P-in-P foals conceived by within-breed artificial insemination. Bodyweight, height at the withers, girth, poll-to-nose length, crown-rump length and three foreleg longbone measuremen...
Webb BA, Barney WE, Dahlman DL, DeBorde SN, Weer C, Williams NM, Donahue JM, McDowell KJ.A new equine abortigenic disease, mare reproductive loss syndrome (MRLS), was recognized and significantly impacted the Ohio Valley in the springs of 2001 and 2002. MRLS caused approximately 330 million US dollars in losses in 2001. An epidemiological investigation of MRLS associated occurrence of the disease with exposure to eastern tent caterpillars (M. americanum). This work investigates the epidemiological association between M. americanum and MRLS to determine if this association was correlative or causative. A pilot study and simulated exposure to M. americanum and their excreta on pastu...
Foote AK, Ricketts SW, Whitwell KE.Significant progress has been made in understanding and monitoring the causes of equine abortion over past decades. However, not all in utero pathology results in abortion. It has long been recognised that some in utero pathology, such as twinning or chronic placentitis, can result in the birth of live but growth-retarded foals and there is historical evidence that birth weight may influence future athletic performance. Clinical experience (e.g. from twins) and experimental studies (pony-Thoroughbred embryo transfer) have highlighted the importance of reduced functional placental area in limit...
Macpherson ML.Equine placentitis, and resultant preterm labor, are important sources of fetal and neonatal loss. The primary cause of equine placentitis is infection of the placenta with Streptococcus equi subspecies zooepidemicus, which ascends through the caudal reproductive tract. Current treatment protocols for mares affected with placentitis are empirical. This paper reviews treatment approaches for resolving placentitis and preterm labor in both equine and non-equine species. Specific therapies reviewed include antimicrobial, anti-inflammatory, tocolytic, and progestin agents.
Wernery U, Knowles NJ, Hamblin C, Wernery R, Joseph S, Kinne J, Nagy P.A virus was isolated from aborted dromedary (Camelus dromedarius) fetuses during an abortion storm in Dubai, United Arab Emirates. Laboratory investigations showed the causative agent to be indistinguishable from equine rhinitis A virus (ERAV), a picornavirus. Two pregnant dromedaries experimentally infected with the camel virus isolate both aborted and an identical virus was reisolated from both fetuses, thus confirming the diagnosis. The extremely high prevalence of antibody (>90 %) and the high titres recorded against ERAV in the dromedary herd clearly showed that ERAV does infect dromedari...
Matheka HD, Coggins L, Shively JN, Norcross NL.EIA virus was purified from equine fetal kidney cell cultures by PEG-precipitation, two sucrose-gradient sedimentations (5-30 per cent) and (25 to 60 per cent) centrifugation, using the immunodiffusion test to follow the procedure. Purified EIA virus had a density (20 degrees C) of 1.162 and a sedimentation constant of S20w=656. electron microscopy revealed a particle of about 100 nm in diameter with a very flexible but usually spherical shape. The dense core may be at various locations inside the membrane bound particle.
de Leon PM, Campos VF, Dellagostin OA, Deschamps JC, Seixas FK, Collares T.In this study, polymerase chain reaction (PCR) reamplification of the first PCR product (2nd-PCR) and a qPCR assay were used to detect the sex determining region Y (SRY) gene from circulating cell-free fetal DNA (ccffDNA) in blood plasma of pregnant mares to determine fetal sex. The ccffDNA was isolated from plasma of 20 Thoroughbred mares (5-13 y old) in the final 3 mo of pregnancy (fetal sex was verified after foaling). For controls, plasma from two non-pregnant mares and two virgin mares were used, in addition to the non-template control. The 182 bp nucleotide sequence corresponding to the ...
Murase H, Miyazawa M, Harada T, Ozawa M, Sato F, Hada T.The degree of fetal growth restriction has been unclear in equine reproduction. In this study, 2,195 fetuses from 2,137 abortions during 11 seasons were examined to determine the causes of abortion, and fetal size dimensions (crown rump length and body weight) were measured. In total, 900 cases (42.1%) of abortion were identified as caused by viral infection (215, 10.1%), bacterial infection (156, 7.3%), fungal infection (25, 1.2%), circulation failure (406, 19.0%), multiple causes (66, 3.1%), deformity (13, 0.6%), placental abnormality (12, 0.6%), and other causes (7, 0.3%). All viral infecti...
Tanaka Y, Taniyama H, Tsunoda N, Shinbo H, Nagamine N, Nambo Y, Nagata S, Watanabe G, Herath CB, Groome NP, Taya K.Immunolocalization of the inhibin (a) and inhibin/activin (beta3A and betaB) subunit proteins in equine fetal testes was investigated to determine the ability of the fetal testis to produce inhibins at 120, 150, 200, and 250 days of gestation. In addition, concentrations of immunoreactive (ir)-inhibin, inhibin pro-aC, and inhibin A in both the maternal and fetal circulation were measured. It was found that plasma concentrations of ir-inhibin, inhibin pro-alphaC, and inhibin A were much higher (P < .05) in the fetal than in the maternal circulation at any stage of gestation examined. Similar...
Bollwein H, Weber F, Woschée I, Stolla R.Transrectal color Doppler sonography was used to investigate uterine and umbilical blood flow during pregnancy (duration, 46-48 weeks) in four mares. The resistance index (RI) and blood flow volume (VOL) of the uterine arteries ipsilateral and contralateral to the conceptus, and the presence of an early diastolic notch in the Doppler wave, were evaluated every 4 week throughout pregnancy. Fetal blood flow was calculated semiquantitatively every 2 week (from 20 to 40 weeks), using the RI of the umbilical arteries. During the entire period of investigation, there were no significant individual v...
Melchert M, Aurich C, Aurich J, Gautier C, Nagel C.Mares usually give birth when they perceive their environment as safe and therefore disturbance at foaling may inhibit labor. In this study, foaling mares were transferred to an unfamiliar environment at rupture of the allantochorion (stress, n = 6) or were left undisturbed (control, n = 5). The progress of foaling, heart rate, heart rate variability (HRV) and plasma catecholamine, oxytocin and cortisol concentration were determined. In stressed mares, time from rupture of the allantochorion to appearance of the fetal feet (5.3 ± 1.1 vs. 1.6 ± 0.4 min) and total length of f...
Peugnet P, Robles M, Wimel L, Tarrade A, Chavatte-Palmer P.The study of early developmental conditioning of health and disease in adulthood is particularly relevant in the horse, which is bred mainly to perform in demanding sport challenges. On the basis of this concept, the management of the broodmare could be considered an effective means to produce animals with the desired features. Knowledge on the Developmental Origins of Health and Disease in the equine species remains relatively scarce, with some experimental studies and one single epidemiologic study. Data highlight the determinant role of the maternal environment for postnatal body conformati...
Esteller-Vico A, Ball BA, Troedsson MHT, Squires EL.Equine pregnancy is characterized by very high circulating concentrations of estrogens. The physiological roles of estrogens during equine gestation are largely unknown, although some studies suggest a role in the regulation of uterine artery hemodynamics and a relationship between low circulating estrogen concentrations and late pregnancy loss. The objectives of this experiment were to evaluate the effects of estrogen suppression on uterine artery hemodynamics and on pregnancy outcome. Estrogen synthesis was suppressed using letrozole, a potent aromatase inhibitor. Twelve pregnant mares were ...
Lanci A, Ingrà L, Dondi F, Tomasello F, Teti G, Mariella J, Falconi M, Castagnetti C.Exfoliative cytology of human amniotic fluid (AF) has been extensively studied since 1940s, but no data exist in equine species. The AF compartment represents the environment in which the foetus grows and matures, and its composition changes, reflecting foetal well-being and development. The aim of this study was to describe for the first time the morphology of equine AF cells and amniotic membrane (AM) with light microscopy (LM) and transmission electron microscopy (TEM). AF was collected at parturition within 5 min after the appearance of the AM with a 60 mL syringe from 34 mares and sampl...
Crossett B, Suire S, Herrler A, Allen WR, Stewart F.One of the major, progesterone-dependent proteins secreted into the uterine lumen of the mare is a 19-kDa lipocalin (P19). It associates strongly with the embryonic capsule that envelops the young horse conceptus in early gestation, suggesting that it may be involved in sustaining early development. However, it was not known whether the protein was transported through the capsule and/or trophoblast layer and into the yolk sac cavity. To address this question, polyclonal antisera were raised against a C-terminal peptide (based on the deduced amino acid sequence of P19) and a recombinant-derived...
Pu Y, Zhang Y, Zhang T, Han J, Ma Y, Liu X.As a nutrient sensor, the placenta plays a key role in regulating fetus growth and development. Long non-coding RNAs (lncRNAs) have been shown to regulate growth-related traits. However, the biological function of lncRNAs in horse placentas remains unclear. To compare the expression patterns of lncRNAs in the placentas of the Chinese Ningqiang (NQ) and Yili (YL) breeds, we performed a transcriptome analysis using RNA sequencing (RNA-seq) technology. NQ is a pony breed with an average adult height at the withers of less than 106 cm, whereas that of YL is around 148 cm. Based on 813 million high...
Henker LC, Lorenzett MP, Keller A, Siqueira FM, Driemeier D, Pavarini SP.Pantoea agglomerans, family Enterobacteriaceae, is a Gram-negative bacterium that may be isolated from soil and from plants. This bacterium has been associated with disease in plants, humans, and rarely in domestic animal species. We describe here a case of fibrinonecrotic placentitis and equine abortion associated with P. agglomerans infection in southern Brazil. A fetus with 10 months of gestation and its placenta were evaluated. Gross lesions were observed in the cervical star extending to the body of the chorioallantois and consisted of a focally extensive, transmural, severely thickened...
Forhead AJ, Broughton Pipkin F, Taylor PM, Baker K, Balouzet V, Giussani DA, Fowden AL.Blood pressure, heart rate and the plasma concentrations of cortisol and components of the renin-angiotensin system were measured in chronically catheterized Pony mares (n=15) and their fetuses during the second half of gestation (day 153-336 of gestation; term is normally between day 320 and day 340 of gestation). Fetal blood pressure increased towards term with the prepartum surge in plasma cortisol concentration, and there was a correlation between fetal blood pressure and both gestational age (r = 0.88, P < 0.0005) and plasma cortisol concentration (r = 0.88, P < 0.0005). Plasma concentrat...
Conley AJ, Ball BA.Historically, studies on the endocrinology of pregnancy and parturition in horses have made major contributions of relevance to mammals in general. Recent use of liquid chromatography mass spectrometry, measuring multiple steroid hormones simultaneously in blood, foetal and placental tissues throughout normal gestation, and in mares with experimentally induced placentitis, has advanced our current understanding of many of the unusual strategies seen during gestation and at foaling. This includes the stimulation of luteal steroidogeneisis by equine chorionic gonadotropin (eCG) from the endometr...
