Gestation in horses refers to the period during which a mare carries a developing fetus, typically lasting around 11 months, or approximately 340 days. This process involves a series of physiological and hormonal changes that support fetal development and prepare the mare for parturition. Key stages of equine gestation include fertilization, embryonic development, and fetal growth, each characterized by specific developmental milestones. Monitoring the health and progress of gestation is essential for ensuring the well-being of both the mare and the foal. This page compiles peer-reviewed research studies and scholarly articles that explore the various aspects of equine gestation, including hormonal regulation, fetal development, and factors influencing gestational length and outcomes.
Malinska M, Havlicek Z, Koru E, Rezac P.Little is known about factors influencing gestation length in heavier types of horses. The objective was to assess the effects of the weight and age of mares, weight and sex of foals, lactation, month and year of conception, month of foaling, stallion and mare on gestation length in the endangered Old Kladruber breed that once served as a heavy coach horse for ceremonies of the Imperial Court in Vienna. The study was performed at the stud farm Slatinany, Czech Republic and reports data from foaling seasons between 2001 and 2018. A total of 649 gestations were included in the study. Gestation i...
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...
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...
Camargo Ferreira J, Linhares Boakari Y, Sousa Rocha N, Saules Ignácio F, Barbosa da Costa G, de Meira C.The present study characterized the luteal status and the dynamic of the conceptus during the first 20 days of gestation in mares with different ages and degrees of endometrial degeneration. Total area of the corpus luteum (CL), luteal vascularity, CL area with blood signals, progesterone concentrations (P4), embryonic vesicle diameter, number of embryonic location changes, embryonic fixation position and uterine contractility were evaluated. In Experiment 1, mares ≤6 years of age (Young group, 5.6 ± 0.2 years, n = 7 mares) and mares ≥15 years of age (Old group, 17.2 ± 0.9 yea...
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...
Lanci A, Castagnetti C, Ranciati S, Sergio C, Mariella J.In the mare, foaling is a critical unpredictable event due to a wide range of gestational length and the absence of clear signs of impending parturition. To predict foaling, pH, inversion sodium potassium and increase of calcium concentration in mammary secretions are used. The aim of this study was to find how many days are left until parturition knowing mare's age (A) and parity (P) combined with ultrasonographic measurements of the fetal orbit in Standardbred mares with normal pregnancy. Eighty healthy Standardbred mares with normal pregnancy were hospitalized for attended delivery. Informa...
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...
Faramarzi B, Rich LJ, Wu J.Pregnancy in many mammals, including mares, is associated with physiological changes that are reflected in hematological and biochemical profiles. Understanding those physiological changes and differentiating them from pathological changes is imperative for providing care and medical therapy in pregnant mares. Our objective was to compare normal hematological and biochemical profiles in healthy non-pregnant as well as healthy pregnant mares during the 1st and 2nd trimesters of pregnancy. Blood was collected by jugular venipuncture into ethylenediaminetetraacetic acid and serum tubes. Whole blo...
Pyles MB, Fowler AL, Bill VT, Crum AD, Hayes SH, Harlow BE, Flythe MD, Lawrence LM.Dietary starch source has been shown to affect fecal bacterial communities of horses fed minimally processed cereal grains. However, processing may increase foregut starch digestibility, reducing effects of starch source on fecal bacterial communities. This study aimed to determine the effect of starch source in pelleted concentrates on fecal Lactobacillus spp., amylolytic bacteria, and cellulolytic bacteria in broodmares mares, during the prepartum and postpartum period. Thoroughbred mares (n = 18) were paired by last breeding date then randomly assigned to either an oat-based or a corn and ...
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...
Karlíková R, Široká J, Mech M, Friedecký D, Janečková H, Mádrová L, Hrdinová F, Drábková Z, Dobešová O, Adam T, Jahn P.The case of atypical myopathy (AM) in newborn Haflinger foal with clinical signs of depression and weakness appearing 6 hours after birth resulting in recumbency 12 hours after birth is described. The foal's dam was diagnosed with AM in the 6th month of gestation based on clinical signs of a myopathy, elevated serum activity of creatine kinase, metabolomic analysis and the presence of methylenecyclopropyl acetyl carnitine (MCPA-carnitine) in the blood. At the time of delivery, the mare was grazing on a pasture near sycamore trees but was free of clinical signs of AM. Metabolomic analysis of th...
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...
Hartmann C, Lidauer L, Aurich J, Aurich C, Nagel C.Observation of preparturient mares is labour-intensive and time requirements would be reduced with automated monitoring systems. Recently, small-size accelerometers have become available. We followed the hypothesis that increased restlessness in mares shortly before the expulsive stage of labour can be detected with such accelerometers. Accelerometers were attached medioventrally to the halter of eight late pregnant mares. To evaluate an influence of accelerometer position, in one mare two additional accelerometers were attached close to the mandibular and atlanto-occipital joints. Acceleromet...
Kimura Y, Sasaki M, Watanabe K, Dhakal P, Sato F, Taya K, Nambo Y.Activin is secreted from equine uterine glands and plays important roles in establishment and maintenance of pregnancy in mares. This study aimed to localize activin receptors (ActRs) IA/B and IIA/B using immunohistochemistry in the uteroplacental tissues of seven pregnant Thoroughbred mares. At the time of tissue collection, the mares were at the following days of pregnancy: 88, 120, 161, 269, 290, 313, and 335 days. We fixed the uteroplacental tissues in 4% paraformaldehyde and obtained serial sections that were subsequently stained for analysis. All four isoforms of ActR were expressed in t...
Gibson C, de Ruijter-Villani M, Rietveld J, Stout TAE.Glucose is the primary energy substrate for early conceptus development and, for the first 40 days of gestation, the equine conceptus depends solely on glucose available in the histotroph; thereafter, histotrophic glucose provision continues to support transport across the definitive placenta. To investigate glucose provision routes during early equine pregnancy we examined expression of glucose transporters in conceptus membranes and endometrium recovered on days 7, 14, 21 and 28 after ovulation. To further differentiate the contributions of maternal progesterone priming and conceptus-endomet...
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...
Rau J, Tiedemann D, Sielhorst J, Tönissen A, Burger D, Martinsson G, Rohn K, Oldenhof H, Sieme H.Transvaginal ultrasound-guided aspiration (TUA) is a procedure which can be used for the reduction of twins post-fixation in the mare. The aim of this study was to evaluate the effect of the age of mares and the day of gestation on the outcome of TUA treatment. Methods: In 88 mares, diagnosed pregnant with twins, TUA of the yolk sac or allantoic fluid was performed between day 30 and 62 of gestation. Mares were aged 3-22 years. Ultrasonographic examination for a viable singleton pregnancy was performed by referring veterinarians 5-7 days and 4 weeks after TUA. Based on reported findings, effec...
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...
Satué K, Marcilla M, Medica P, Cravana C, Fazio E.Growth hormone (GH) and insulin-like growth factor (IGF-I) exert essential functions to maintain an adequate metabolic activity for correct placental and fetal development. Although fructosamine (FRUCT) is used in clinical evaluation to assess the glycaemic state, the relationships between GH, IGF-I and FRUCT remain unknown in the mare. Therefore, the objectives of this study were to evaluate the relationships among these parameters 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. Serum...
Satué K, Marcilla M, Medica P, Ferlazzo A, Fazio E.The objectives of this study were to establish reference values for serum concentrations of placental growth factor (PlGF) and haptoglobin (Hp), and to analyze whether the levels of oestrone sulphate (E1S) and progesterone (P4) are physiologically involved in the dynamic modifications of the above parameters in pregnant mares. A total of 30 healthy Spanish Purebred mares ranging in age 9.33 ± 3.31 years were studied during the 11 months of gestation. Serum concentrations of PlGF were detected by EIA, Hp using commercial Phase Haptoglobin assay and E1S and P4 levels through RIA. The serum ...
Smits K, Willems S, Van Steendam K, Van De Velde M, De Lange V, Ververs C, Roels K, Govaere J, Van Nieuwerburgh F, Peelman L, Deforce D, Van Soom A.During maternal recognition of pregnancy (MRP), a conceptus-derived signal leads to the persistence of the corpus luteum and the maintenance of gestation. In the horse, the nature of this signal remains to be elucidated. Several studies have focused on the changes in gene expression during MRP, but little information exists at the protein level. The aim of this study was to identify the proteins at the embryo-maternal interface around signalling of MRP in the horse (day 13) by means of mass spectrometry. A distinct influence of pregnancy was established, with 119 proteins differentially expres...
Mariella J, Iacono E, Lanci A, Merlo B, Palermo C, Morris L, Castagnetti C.The umbilical cord (UC), the connection between mother and fetus via the umbilical vessels, carries nutrients and oxygenated blood to the fetus through the umbilical vein and removes deoxygenated blood and waste products via the umbilical arteries. It is designed to protect blood flow to the fetus during pregnancy. In equine medicine, only a few studies have described the UC, and most of these involved Thoroughbreds. The present study describes and compares the macroscopic features of the equine umbilical cord in three different breeds and in relation to the foal's gender. In addition, a possi...
Schöniger S, Gräfe H, Richter F, Schoon HA.The enzyme indoleamine 2,3-dioxygenase 1 (IDO1) acts immunomodulatory and restricts bacterial growth. In the uterus of women and mice, it likely contributes to tissue homeostasis and disease pathogenesis. Pregnancy failure in mares is often caused by endometritis and endometrosis. The pathogenesis of nonsuppurative endometritis and endometrosis is still uncertain. To the authors' knowledge, no information on IDO1 expression in the equine endometrium is published. Aim of this study was to examine the presence of IDO1 as transcripts and proteins in the healthy and diseased endometrium of 25 mare...
Bromfield JJ.Artificial insemination has been a landmark procedure in improving animal agriculture over the past 150 years. The utility of artificial insemination has facilitated a rapid improvement in animal genetics across agricultural species, leading to improvements of growth, health and productivity in poultry, swine, equine and cattle species. The utility of artificial insemination, as with all assisted reproductive technologies side-steps thousands of years of evolution that has led to the development of physiological systems to ensure the transmission of genetics from generation to generation. The ...
Olivera R, Moro LN, Jordan R, Pallarols N, Guglielminetti A, Luzzani C, Miriuka SG, Vichera G.Cell plasticity is crucial in cloning to allow an efficient nuclear reprogramming and healthy offspring. Hence, cells with high plasticity, such as multipotent mesenchymal stem cells (MSCs), may be a promising alternative for horse cloning. In this study, we evaluated the use of bone marrow-MSCs (BM-MSCs) as nuclear donors in horse cloning, and we compared the in vitro and in vivo embryo development with respect to fibroblasts. Methods: Zona-free nuclear transfer was performed using BM-MSCs (MSC group, n=3432) or adult fibroblasts (AF group, n=4527). Embryos produced by artificial insemination...
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 ...
Anderson ST, Kidd LJ, Barton AJ, Greer RM.Breeding mares typically foal yearly. Little is known about the dynamics of maternal bone stores during gestation and lactation, the timing of any maternal bone mobilisation, re-accretion post-foaling, or the dynamics of bone metabolism in foals. We measured serum osteocalcin (OC) and serum pyridinoline (PYD) concentrations in 18 mares monthly from 6months gestation to foaling, and in both mares and foals for 4months after birth. From 6 to 11months of gestation, there was no change in mean monthly OC. Serum PYD increased between 7months gestation and foaling. After foaling, mean serum OC was l...
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...
Betteridge KJ, Raeside JI, Waelchli RO, Christie HL, Hayes MA.Sixteen cases of spontaneous pregnancy loss (11 of singletons and five of pairs of twins) are described. The losses occurred between gestation Days 13 and 25 in 12 mares being monitored almost daily by transrectal ultrasonography (for measurement of conceptus growth) and blood sampling (for determination of maternal plasma progesterone concentrations as evidence of luteolysis) in experimental studies of early pregnancy. In 10 of the 16 cases the uterus was flushed and eight conceptuses were recovered for morphological assessment. Five of the 11 losses of singletons occurred before Day 16 and, ...
Gee E, Davies M, Firth E, Jeffcott L, Fennessy P, Mogg T.Copper (Cu) supplementation of dams in late gestation may be protective against articular cartilage abnormalities in foals. Articular cartilage was harvested from 22 Thoroughbred foals at 160 days of age, at sites predisposed to osteochondrosis (OC), and examined for evidence of early cartilage abnormalities and established dyschondroplastic (DCP) lesions to determine if there were any significant differences due to mare Cu supplementation by injection during late gestation, or foal liver Cu concentration. Cu supplemented mares received calcium Cu edetate injections in late gestation (250 mg a...
Karlíková R, Široká J, Mech M, Friedecký D, Janečková H, Mádrová L, Hrdinová F, Drábková Z, Dobešová O, Adam T, Jahn P.The case of atypical myopathy (AM) in newborn Haflinger foal with clinical signs of depression and weakness appearing 6 hours after birth resulting in recumbency 12 hours after birth is described. The foal's dam was diagnosed with AM in the 6th month of gestation based on clinical signs of a myopathy, elevated serum activity of creatine kinase, metabolomic analysis and the presence of methylenecyclopropyl acetyl carnitine (MCPA-carnitine) in the blood. At the time of delivery, the mare was grazing on a pasture near sycamore trees but was free of clinical signs of AM. Metabolomic analysis of th...
Rodrigues MN, Carvalho RC, Franciolli AL, Rodrigues RF, Rigoglio NN, Jacob JC, Gastal EL, Miglino MA.Since the horse has a highly precocial reproductive strategy, most organs are functionally well developed at birth and thus, embryonic and fetal life is interesting. Data on the development of important organs are very limited. Here, we detailed macroscopically and histologically the equine digestive system, focusing on the first third of gestation. At 21 days, the oral cavity was an empty space, and the liver contained proliferating endodermal cells. At 25 days, a fusiform stomach and the pancreatic bud were present. At 28 days, a small tongue and the esophagus occurred. At 30 days, primary a...
Dini P, Kalbfleisch T, Uribe-Salazar JM, Carossino M, Ali HE, Loux SC, Esteller-Vico A, Norris JK, Anand L, Scoggin KE, Rodriguez Lopez CM, Breen J....Most autosomal genes in the placenta show a biallelic expression pattern. However, some genes exhibit allele-specific transcription depending on the parental origin of the chromosomes on which the copy of the gene resides. Parentally expressed genes are involved in the reciprocal interaction between maternal and paternal genes, coordinating the allocation of resources between fetus and mother. One of the main challenges of studying parental-specific allelic expression (allele-specific expression [ASE]) in the placenta is the maternal cellular remnant at the fetomaternal interface. Horses () ha...
Heidler B, Aurich JE, Pohl W, Aurich C.This study summarizes weight development, plasma glucose concentrations and reproductive parameters in lactating (n = 46) and non-lactating Lipizzaner mares (n = 11) throughout the breeding season. It was the aim of the study to analyse if an energy deficit with possible effects on reproductive functions occurs at any time during the first 4 months of gestation. Mean gestation length was 334.3 +/- 7.3 days. Gestation of foals born in May/June was shorter (P < 0.01) than for foals born in March/April. Out of the 46 lactating mares, 44 ovulated between Days 8 and 18 postpartum and two mares ovul...
Wilsher S, Allen WR.Eight day 10 horse embryos were transferred non-surgically to recipient mares that had ovulated 7 days after the donors. The embryonic vesicle was seen ultrasonographically in all eight recipients, and three out of eight (38%) of the vesicles developed an embryo proper with a beating heart. Conceptus expansion was initially slower than that in control mares but continued until day 22 (recipient day 15). Time of fixation of the vesicle was related to its diameter, rather than uterine stage. Although the embryo proper first appeared ultrasonographically on day 22, as normal, it grew more slowly ...
Zhao Q, Tao C, Pan J, Wei Q, Zhu Z, Wang L, Liu M, Huang J, Yu F, Chen X, Zhang L, Li J.Fixed-time artificial insemination (FTAI) technology uses exogenous reproductive hormones to regulate the sexual cycle and ovulation of sows without oestrus identification, which improves the sow breeding utilisation rate, reduces the number of non-productive days, and elevates the efficiency of pig farm management. In this study, we aimed to optimise FTAI procedures. Healthy 190-day-old and about 90 kg Large White × Landrace crossing breed replacement gilts (n = 166) which were of unknown reproductive status were randomly selected and divided into three groups: a control group (n = 62...
Loux SC, Scoggin KE, Troedsson MH, Squires EL, Ball BA.The cervical mucus plug (CMP) is believed to play an integral role in the maintenance of pregnancy in the mare, primarily by inhibiting microbial entry. Unfortunately, very little is known about its composition or origin. To determine the proteomic composition of the CMP, we collected CMPs from mares (n = 4) at 9 months of gestation, and proteins were subsequently analyzed by nano-LC-MS/MS. Results were searched against EquCab2.0, and proteomic pathways were predicted by Ingenuity Pathway Analysis. Histologic sections of the CMP were stained with H&E and PAS. To identify the origin of ...
Turner RM, McDonnell SM, Feit EM, Grogan EH, Foglia R.Ultrasonographic fetal eye measures have been used to estimate gestational age of the fetus in light horse mares. However, fetal eye measures have not been published for smaller pony breeds. This study was conducted to develop reference ranges for ultrasonographic measures of fetal eyes in small ponies for the purpose of predicting days before parturition (DBP) when breeding or ovulation dates are unknown. Twenty-three Shetland-type pony mares were studied across one (n = 10) or two (n = 13) gestations in 2004 (18 pregnancies) and 2005 (18 pregnancies). Measurements of fetal eyes were obtained...
Erol E, Jackson C, Horohov D, Locke S, Smith J, Carter C.Determination of fetal serum amyloid A (SAA) concentrations in aborted fetuses can provide valuable information regarding the infectious and/or inflammatory process of abortion in horses. To investigate the relationship between fetal SAA levels and the infectious/inflammatory disease process in feto-placental tissues, a SAA ELISA was used to test heart serum samples of 89 equine fetuses that were necropsied and diagnosed in the following groups: a multiorgan disease process diagnosed with an identified microorganism (14 cases, group 1); only placentitis diagnosed with an identified microorgan...
Rivera Del Alamo MM, Katila T, Palviainen M, Reilas T.Intrauterine devices block luteolysis in cyclic mares, but the underlying mechanism is unknown. To clarify the mechanisms, the protein profile of the endometrial secretome was analyzed using two-dimensional difference gel electrophoresis (2D-DIGE). Twenty-seven mares were classified according to whether they were inseminated (AI) or had an intrauterine device (IUD), a water-filled plastic sphere, inserted into the uterus on Day 3 after ovulation. Uterine lavage fluids were collected on Day 15 from pregnant inseminated mares (AI-P; n = 8), non-pregnant inseminated mares (AI-N; n = 4), and m...
Wilsher S, Allen WR.The development of the equine placenta involves a series of stage-specific events which ensure that the fetus is nourished throughout its 11 months of gestation. Initially, placental exchange to the developing embryo is histotrophic, via the yolk sac but, as the allantochorion develops and microcotyledons form, haemotrophic nutrition plays the major role in sustaining the increasing demands of the growing fetus. This review describes the development of the allantochorionic placenta of the mare and discusses some of the factors that influence its growth, size and functions and, hence, its contr...
Joonè CJ, Bertschinger HJ, Gupta SK, Fosgate GT, Arukha AP, Minhas V, Dieterman E, Schulman ML.Few studies have investigated ovarian function in the mare undergoing porcine zona pellucida (pZP) immunocontraception despite reported ovarian dysfunction in other species. Objective: This study aimed to describe ovarian function and oestrous cyclicity in pony mares following treatment with either the conventional pZP vaccine or a novel recombinant form of the vaccine derived from porcine ZP3 and ZP4 (reZP). In addition, the contraceptive efficacy of pZP vs. reZP was assessed. Methods: Blinded, randomised, prospective clinical trial. Methods: Mares (n = 21) were randomised into 3 groups of 7:...
Barreto Rda S, Rodrigues MN, Carvalho RC, De Oliveira E Silva FM, Rigoglio NN, Jacob JC, Gastal EL, Miglino MA.Musculoskeletal system development involves heterotypical inductive interactions between tendons, muscles, and cartilage and knowledge on organogenesis is required for clarification of its function. The aim of this study was to describe the organogenesis of horse musculoskeletal system between 21 and 105 days of gestation, using detailed macroscopic and histological analyses focusing on essential developmental steps. At day 21 of gestation the skin was translucid, but epithelial condensation and fibrocartilaginous tissues were observed on day 25 of pregnancy. Smooth muscle was seen in lymphat...
Diel de Amorim M, Khan FA, Chenier TS, Scholtz EL, Hayes MA.The objective of this study was to evaluate the differences in the uterine flush fluid proteome between healthy mares and mares with endometritis or fibrotic endometrial degeneration (FED). Uterine flush fluid samples were collected from healthy mares (n=8; oestrus n=5 and dioestrus n=3) and mares with endometritis (n=23; oestrus n=14 and dioestrus n=9) or FED (n=7; oestrus n=6 and dioestrus n=1). Proteomic analysis was performed using label-free liquid chromatography-tandem mass spectrometry. Of 216 proteins identified during oestrus, 127 were common to all three groups, one protein was exclu...
Stasiak K, Dunowska M, Rola J.Equid herpesvirus 1 (EHV-1) infections are endemic worldwide, including Poland. Many are subclinical, but some are associated with respiratory disease, abortion, neonatal foal death, or neurological disease. We describe an outbreak of abortions in Arabian mares at a well-managed State stud farm in Poland. Methods: Eight of 30 pregnant mares aborted and one gave birth to a weak foal that died within 72 h after birth. EHV-1 was isolated from all fetuses as well as from the diseased foal. All viruses belonged to the N variant based on the predicted open reading frame (ORF) 30 amino acid sequenc...
Sieme H, Katila T, Klug E.This study analyzed effects of different methods and intervals of semen collection on the quantity and quality of fresh, cool-stored, and frozen-thawed sperm and fertility of AI stallions. In Experiment 1, ejaculates were obtained from six stallions (72 ejaculates per stallion) using fractionated versus non-fractionated semen collection techniques. Initial sperm quality of the first three jets of the ejaculate was not different from that of total ejaculates. Centrifugation of sperm-rich fractions before freezing improved post-thaw motility and sperm membrane integrity when compared to non-cent...
Leon A, Pillon C, Tebourski I, Bruyas JF, Lupo C.Abortions in horses represent an important health and economic challenge for equine industry. Primary causes of abortion are divided in non-infectious and infectious. Non-infectious causes include abnormalities of foetal appendices (umbilical cord and placenta essentially), abnormalities of gestation, maternal and foetal origins. Infectious abortions are caused in almost cases by bacterial infections, followed by viruses, fungi and parasites. New abortive pathogens (as Leptospira, Neospora caninum, Coxiella burnetii, Chlamydophila abortus, and) have been confirmed in equines by comparison alre...
Turner JW, Liu IK, Kirkpatrick JF.Regulation of local overpopulations of free-roaming feral equids is in demand worldwide for ecological balance and habitat preservation. Contraceptive vaccines have proven effective in feral horses, which breed seasonally, but no data are available for equids such as the burro, which is reproductively active all year round. In the present study, 27 individually identified female feral burros (Equus asinus) roaming free in Virgin Islands National Park (St John, US Virgin Islands; Lesser Antilles) were remotely treated with pig zonae pellucidae (PZP) vaccine. Between January and May, 16 burros w...
Ousey JC.Evaluation of hormone profiles in late pregnancy is one of the major determinants of fetoplacental compromise in equine clinical practice. Use of hormone therapies is subjective and reflects, to a large extent, our lack of understanding about the endocrine relations between the mare, placenta, and fetus. This article describes the normal endocrine events in late gestation, the abnormal hormone patterns associated with fetoplacental dysfunction, and the hormone interventions that are currently used or could be used to improve pregnancy outcome.
Hartmann C, Lidauer L, Aurich J, Aurich C, Nagel C.Observation of preparturient mares is labour-intensive and time requirements would be reduced with automated monitoring systems. Recently, small-size accelerometers have become available. We followed the hypothesis that increased restlessness in mares shortly before the expulsive stage of labour can be detected with such accelerometers. Accelerometers were attached medioventrally to the halter of eight late pregnant mares. To evaluate an influence of accelerometer position, in one mare two additional accelerometers were attached close to the mandibular and atlanto-occipital joints. Acceleromet...
de Ruijter-Villani M, Deelen C, Stout TA.Leukaemia inhibitory factor (LIF) plays a critical role in blastocyst development and implantation in several species. The present study investigated mRNA and protein expression for LIF, as well as the low-affinity LIF receptor (LIFR) and interleukin-6 signal transducer (IL6ST), in equine endometrium, trophoblast and histotroph during early pregnancy and in the endometrium during the oestrous cycle. Endometrial LIF mRNA expression was upregulated after Day 21 of pregnancy, whereas LIF immunoreactivity increased in the endometrium on Day 28. Expression of LIF mRNA in the yolk sac membrane incre...
Holtan DW, Squires EL, Lapin DR, Ginther OJ.Pony mares were bilaterally ovariectomized at different stages of pregnancy between Days 25 and 210. Abortion or fetal resorption occurred within 2 to 6 days after operations in all 14 mares ovariectomized between Days 25 and 45 and after an interval of 10 to 15 days in 9 of 20 other ovariectomized between 50 and 70 days. All 12 mares ovariectomized on either 140 or 210 days carried their foals to normal term. The termination of early pregnancy was preceded by a loss of uterine tone and of a palpable uterine bulge. The mean length of gestation in all mares in which pregnancy was not interrupte...
Faramarzi B, Rich LJ, Wu J.Pregnancy in many mammals, including mares, is associated with physiological changes that are reflected in hematological and biochemical profiles. Understanding those physiological changes and differentiating them from pathological changes is imperative for providing care and medical therapy in pregnant mares. Our objective was to compare normal hematological and biochemical profiles in healthy non-pregnant as well as healthy pregnant mares during the 1st and 2nd trimesters of pregnancy. Blood was collected by jugular venipuncture into ethylenediaminetetraacetic acid and serum tubes. Whole blo...
Mancill SS, Blodgett G, Arnott RJ, Alvarenga M, Love CC, Hinrichs K.3 sets of monozygotic twins resulting from transfers of single embryos to recipient mares were examined. Results: In all 3 recipient mares with twin pregnancies, only 1 embryonic vesicle was detected before day 25 of gestation. In 1 recipient mare, 2 apparent adjacent vesicles, each containing an embryo with a heartbeat, were visualized on ultrasonographic examination on day 37 of gestation. The other 2 recipient mares underwent ultrasonographic examination on day 30 of gestation, at which time only 1 vesicle and embryo was identified. In these latter 2 recipient mares, however, a thorough ult...
Satué K, Marcilla M, Medica P, Ferlazzo A, Fazio E.The objectives of this study were to establish reference values for serum concentrations of placental growth factor (PlGF) and haptoglobin (Hp), and to analyze whether the levels of oestrone sulphate (E1S) and progesterone (P4) are physiologically involved in the dynamic modifications of the above parameters in pregnant mares. A total of 30 healthy Spanish Purebred mares ranging in age 9.33 ± 3.31 years were studied during the 11 months of gestation. Serum concentrations of PlGF were detected by EIA, Hp using commercial Phase Haptoglobin assay and E1S and P4 levels through RIA. The serum ...
Rosales C, Krekeler N, Tennent-Brown B, Stevenson MA, Hanlon D.To describe selected periparturient variables in a sample of Thoroughbred mares and their foals on a commercial stud farm in New Zealand. Methods: Data were collected for 969 foaling records, from 592 mares, by foaling attendants from one Thoroughbred stud farm in the Waikato region of New Zealand for the breeding seasons 2008-2013, inclusive, and collated retrospectively. The associations between mare- and foal-level variables and gestation length, time of birth (expressed as the number of hours after midday), fetal membrane retention time, time for the foal to stand and suckle after birth, a...
Allen WR.The influence of fetal genotype upon gonadotrophin (PMSG) and progestagen production in mares and donkeys during the first half of pregnancy was examined. The production of PMSG was greatly reduced in mares carrying mule conceptuses and greatly increased in donkeys carrying hinny conceptuses. Fetal genotype had no obvious influence upon progestagen production in mares, but donkeys carrying hinny conceptuses showed extremely high peripheral plasma progestagen concentrations when serum PMSG levels were elevated. Fetal genotype profoundly influences the intensity and rate of success of the matern...
