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.
Yang F, Li N, Liu B, Yu J, Wu S, Zhang R, Yang W, Ji C, Sun Q, Ma J, Li M, Zhou J, Zhou X, Pietrani M, Losinno L, Zeng S.With the expansion of the donkey industry, timed artificial insemination (TAI) is becoming increasingly important in the reproductive management of jennies, however, TAI has not been widely investigated in donkeys. Objective: To develop efficient TAI protocols for cooled or frozen semen in jennies, based around ovulation induction with a GnRH analogue. Methods: Experimental exploratory study. Results: In experiment 1, the effects of different GnRH analogue (deslorelin) doses, follicle diameter (FD) at induction, repeated use of a GnRH analogue, and the influence of season on induction efficien...
Joonè CJ, Gradil CM, Picard JA, Taylor JD, de Tonnerre D, Cavalieri J.The primary aim of this study was to investigate the contraceptive efficacy of a self-assembling uterine device (iUPOD™) in the mare. In addition, the effects of iUPODs on oestrous cyclicity, uterine health and circulating concentrations of cortisol were evaluated. Methods: Domestic mares underwent oestrous monitoring and artificial insemination. After subsequent ovulation, mares underwent either placement (n = 7) or sham placement (n = 7; controls) of an iUPOD device. Devices were left in place for at least 3 months. Pregnancy diagnoses were carried out 14 days post-ovulation, with any pr...
Wilsher S, Rigali F, Kovacsy S, Allen WT.Successful vitrification of equine expanded blastocysts requires collapse of the blastocoele cavity using a micromanipulator-mounted biopsy pipette on an inverted microscope. Such equipment is expensive and requires user skill. Objective: To develop a manual method of blastocoele collapse prior to vitrification using commercial products. Methods: In vivo experiment. Methods: Seventy-nine Day 7 or 8 embryos were measured and graded. Twenty were vitrified following micromanipulator-assisted puncture and aspiration before being used to validate commercial human vitrification and warming kits cont...
Macan RC, Camargo CE, Zielinski BL, Cardoso NGH, de Lara NSS, Bergstein-Galan TG, Weiss RR, Kozicki LE.Timed artificial insemination (TAI) has boosted the use of conventional artificial insemination (CAI) by employing hormonal protocols to synchronize oestrus and ovulation. This study aimed to evaluate the efficiency of a hormonal protocol for TAI in mares, based on a combination of progesterone releasing intravaginal device (PRID), prostaglandin (PGF2α ) and human chorionic gonadotropin (hCG); and compare financial costs between CAI and TAI. Twenty-one mares were divided into two groups: CAI group (CAIG; n = 6 mares; 17 oestrous cycles) and TAI group (TAIG; n = 15 mares; 15 oestrous cycle...
Alves NC, Diniz SA, Viegas RN, Cortes SF, Costa ED, Freitas MM, Martins-Filho OA, Araújo MSS, Lana ÂMQ, Wenceslau RR, Lagares MA.The aim of this study was to improve the quality of frozen-thawed equine sperm by the addition of caffeine to it. Semen from nine stallions was frozen and different concentrations of caffeine (3, 5 and 7.5 mM) were added to frozen-thawed semen. The sperm kinetic parameters, membrane functionality and integrity, and acrosome integrity and spontaneous acrosome reacted sperm were evaluated with a computer-assisted sperm analysis, a hypoosmotic swelling test and epifluorescent microscopy, respectively. Nitrite and hydroperoxide concentrations of frozen-thawed semen were measured using spectrophot...
El-Sheikh Ali H, Dini P, Scoggin K, Loux S, Fedorka C, Boakari Y, Norris J, Esteller-Vico A, Kalbfleisch T, Ball B.Improved understanding of the molecular mechanisms underlying ascending equine placentitis holds the potential for the development of new diagnostic tools and therapies to forestall placentitis-induced preterm labor. The current study characterized the equine placental transcriptome (chorioallantois [CA] and endometrium [EN]) during placentitis (placentitis group, n = 6) in comparison to gestationally-matched controls (control group, n = 6). Transcriptome analysis identified 2953 and 805 differentially expressed genes in CA and EN during placentitis, respectively. Upstream regulator analys...
Alamaary M, Ali A.This report presents a case of uterine prolapse in a Thoroughbred mare. The uterine prolapse occurred after abortion of twins in the eighth month of gestation. The prolapsed uterus was bleeding and congested but not damaged. The placenta was still attached to the endometrium. Blood samples were collected for hematology and for estimation of calcium, progesterone and estrogen. The cervix and clitoris were swabbed for bacteriology. The mare showed a decrease in the number of lymphocytes. The concentrations of estrogen and progesterone seemed normal compared with mares that foaled. Pseudomonas ae...
Roach JM, Foote AK, Smith KC, Verheyen KL, de Mestre AM.Pregnancy loss after Day 70 of gestation manifests as abortion, stillbirth or perinatal death. While previous studies have reported the diagnoses of laboratory submissions, none have quantified the incidence and causes of abortions, stillbirths and perinatal mortality at a population level. Objective: To report the incidence and causes of pregnancy loss after Day 70 of gestation in a cohort of Thoroughbreds. Methods: Retrospective cohort study. Methods: Outcomes of Day 70 pregnancies were collected from eight Thoroughbred farms over the 2013-2017 breeding seasons. Stud, veterinary and laborato...
Kadivar A, Rashidzadeh H, Davoodian N, Nazari H, Dehghani Tafti R, Heidari Khoei H, Seidi Samani H, Modaresi J, Ahmadi E.Accurate diagnosis of foetal sex in pregnant mare is helpful for many breeders, both for private or commercial purposes. In this study, in order to pre-natal foetal sexing in equine, we used TaqMan duplex real-time PCR to detect the specific regions of SRY and TSPY genes on extracted cell-free foetal DNA from maternal blood. Peripheral blood samples from 50 pregnant Arabian mares with singleton foetuses were collected. Cell-free foetal DNA was extracted from maternal plasma, and duplex real-time PCR assays were performed with TaqMan probes and primers. Amplification of glyceraldehyde-3-phospha...
Diaz-Jimenez M, Rota A, Dorado J, Consuegra C, Pereira B, Camillo F, Panzani D, Fanelli D, Tesi M, Monaco D, Hidalgo M.Sperm vitrification has been recently developed, but fertility trials have not been performed yet in equine species. In this study, a new warming technique for vitrified donkey semen was developed and the uterine inflammatory response and fertility were compared to conventional freezing. In Experiment 1, sperm was vitrified in straws and warmed in 3 ml of extender or in a water bath at: 37 °C/30 s; 43 °C/10 s; and 60 °C/5 s. Sperm motility, plasma and acrosome membranes and DNA integrity were compared between treatments. In Experiment 2, jennies were inseminated twice (500 Ã...
Mure S, Oishi K, Hirooka H.The objective of the present study was to develop a deterministic simulation model for evaluating the reproductive performance of Thoroughbred mares. As an application, the model was used to estimate the herd level asymptotic foaling percentage (AFP) for evaluating the performance of mares in stabilized mare herds using the convergent method for estimating a steady-state distribution of mares. In this model, it was assumed that the mares were mated only during the breeding season. The effects of early pregnancy loss and fetal loss on reproductive performance were investigated. The sensitivitie...
Okada CTC, Kaps M, Perez Quesada J, Gautier C, Aurich J, Aurich C.Spontaneous prolongation of the luteal phase has been described in horses, but the underlying causes are still unclear. The present study investigated details of gonadotrophin and progestogen secretion in pregnant mares (n = 11) with or without experimentally reduced early postovulatory luteal function. From days 0 to 3 after ovulation, they were treated with the prostaglandin F (PGF) analogue cloprostenol or left untreated. After conceptus collection on day 34, they were assigned to the opposite treatment. Mares were affiliated to the group primary corpus luteum (n = 6) or diestrous corpus lu...
Rodriguez J, Maserati M, Robilotta T, Augusto G, Alonso MA, Redoan M, Tibary A, Fleury P.Field collection of oocytes in mares using transvaginal follicular aspiration (TVA) for embryo production has the potential to revolutionate the equine industry. Protocols for TVA in specialized laboratory settings have been described in the scientific literature since the early 1980s. The objective of this study was to determine the success rate of TVA oocytes recovery under ambulatory conditions. A secondary goal of this study was to determine if TVA is associated with any health complications when performed by recently trained practitioners in the field. Follicles (n = 296) from 66 adult c...
Danyer E, Bilal T.The effects of fish oil (40 ml/day) supplementation, with or without synthetic all-rac-alpha-tocopherol-acetate (2,500 IU/day), during the last 65 days before expected parturition were investigated in 15 adult mares (553 ± 24 kg BW) and their foals. Mares were assigned to one of three diets: control (n = 5), control plus fish oil and alpha-tocopherol (n = 4; FO + AT) or control with just fish oil (n = 6; FO). Blood samples were obtained from the mares before a 15-day dietary adaptation period (T1) and from mares and foals the first (T2) and fifth (T3) days post-partum. Colostrum...
Rigoleto Júnior WL, Dias de Camargo Neto W, de Paula Nogueira G, Ferrari TA, Bertan Membrive CM, Giometti IC, Castilho C.The objective of this study was to quantify serum progesterone levels, uterine features, and pregnancy rates in acyclic, embryo recipient mares using a bovine progesterone-releasing intravaginal device in a commercial embryo transfer (ET) program. The study included 73 recipient mares of unknown breed, aged 3-10 years, weighing 350-500 kg, and kept under an intensive management system on Tifton 85 (Cynodon spp.) pastures with water and mineral salt ad libitum. The horses were divided into two groups: a group with a progesterone-releasing intravaginal device (1 g progesterone, G-IVP4, n = 24...
Vilaregut L, Lores M, Wilsher S.This review details the current state of knowledge about the equine yolk sac and its remnant (YSR) in the pregnant mare, which, incidentally, is the only animal species known to exhibit large and/or ossified YSR. It also describes the clinical significance of the YSR and details a case of a strangulating YSR that caused fetal death and abortion.
Boakari YL, El-Sheikh Ali H, Schnobrich M, Lofrumento K, Scoggin C, Bradecamp E, Scoggin K, Esteller-Vico A, Claes A, Lawrence L, Ball B.High blood urea nitrogen (BUN) concentration is linked to low fertility in cows and ewes; however, this relationship has not been reported in mares. The study characterized the relationship between BUN and follicular fluid urea nitrogen (FUN) during follicle growth (Experiment 1) and the impact of BUN from embryo donors on the pregnancy outcome of recipient mares (Experiment 2). In experiment one, follicular fluid and blood samples were collected from mares during diestrus with growing follicles and during estrus with pre-ovulatory follicles (n = 16 and 10 mares, respectively). In experiment...
Ignácio FS, Montechiesi DF, Bergfelt DR, Orlandi CMB, Carvalho LR, Puoli Filho NJ, Meira C.The present study was designed to evaluate luteinization rates subsequent to aspiration of dominant follicles (≥25 mm) in the absence of a functional CL (progesterone <1 ng/mL) and characterize the temporal changes in plasma concentrations of progesterone following aspiration-induced luteinization during the estrous cycle in mares. A total of 29 estrous cycles involving 15 mares in a cross-over design were randomly assigned to five groups: 1) ASP-F≥25 mm (n = 6; follicle aspiration 25-29 mm), 2) ASP-F≥30 mm (n = 6; follicle aspiration 30-34 mm), 3) ASP-F≥35 mm (n = 6; foll...
El-Sheikh Ali H, Scoggin K, Linhares Boakari Y, Dini P, Loux S, Fedorka C, Esteller-Vico A, Ball B.Placenta-specific 8 (PLAC8) is one of the placenta-regulatory genes which is highly conserved among eutherian mammals. However, little is known about its expression in equine placenta (chorioallantois; CA and endometrium; EN) during normal and abnormal pregnancy. Therefore, the current study was designed to 1) elucidate the expression of PLAC8 in equine embryonic membranes during the preimplantation period, 2) characterize the expression profile of PLAC8 in equine CA (45d, 4mo, 6mo, 10 mo, 11 mo and postpartum) and EN (14d, 4mo, 6mo, 10 mo, and 11 mo) obtained from pregnant mares (n = 4/...
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...
Wang X, Ji Y, Su J, Xue Y, Xi H, Wang Z, Bi L, Zhao R, Zhang H, Yang L, Guo Z, Guan Y, Feng X, Sun C, Lei L, Ur Rahman S, Dong J, Han W, Gu J. subsp. serovar Abortusequi is a frequently reported pathogen causing abortion in mares. In this study, the preventive and therapeutic effects of phage P SAE-01E2 against Abortusequi in a mouse model of abortion were investigated. Phage P SAE-01E2 was stable at different temperatures (4 to 70°C) and pH values (pH 4 to 10) and could lyse the majority of the serogroup O:4 and O:9 strains tested (25/28). There was no lysogeny-related, toxin, or antibiotic resistance-related gene in the genome of P SAE-01E2. All of these characteristics indicate that P SAE-01E2 has the potential for use in pha...
Boakari YL, El-Sheikh Ali H, Dini P, Loux S, Fernandes CB, Scoggin K, Esteller-Vico A, Lawrence L, Ball B.High blood urea nitrogen (BUN) in cows and ewes has a negative effect on embryo development; however, no comparable studies have been published in mares. The aims of the present study were to evaluate the effects of high BUN on blastocoele fluid, systemic progesterone and Day 14 equine embryos. When a follicle with a mean (±s.e.m.) diameter of 25±3mm was detected, mares were administered urea (0.4g kg-1) with sweet feed and molasses (n=9) or sweet feed and molasses alone (control; n=10). Blood samples were collected every other day. Mares were subjected to AI and the day ovulation was detect...
Kammerer R, Ballesteros A, Bonsor D, Warren J, Williams JM, Moore T, Dveksler G.In early equine pregnancy, a highly invasive trophoblast cell subpopulation, the chorionic girdle cells, invade the endometrium and form endometrial cups (EC). These cells express classical MHC molecules, thereby stimulating a humoral and cellular immune response, resulting in a massive accumulation of maternal CD4+ and CD8+ T cells around the EC. Nevertheless, no immediate destruction of endometrial cups by maternal lymphoid cells occurs, presumably due to immune tolerance. Although the environment of EC is rich in TGFB and in FOXP3+, CD4+ T cells, the mechanisms leading to tolerance have not...
Checura CM, Momont HW, Castañeira C, Flores-Bragulat A, Losinno L.In horses, prostaglandin E (PGE) is produced by embryos around Day 5 post-ovulation; PGE functions directly at the oviduct promoting embryo transport into the uterus. Non-surgical collection of horse embryos for cryopreservation is recommended at Day 6.5-7 post-ovulation. It was proposed that misoprostol administered orally will hasten oviductal transport of horse embryos. In Experiment 1 (n = 15) there was comparison of time of embryo recovery (Day 6 and 6.5 post-ovulation) from mares administered misoprostol (Day 5 and 5.5) orally to that of untreated mares. On Day 6, embryo collections were...
Carluccio A, Veronesi MC, Plenteda D, Mazzatenta A.The chronic degenerative endometritis (CDE) is recognised as directly related to age and infertility in the mare. In this study, the 14 days post ovulation (PO) pregnancy rate was assessed in 60 barren mares affected by CDE, submitted to platelet-rich-plasma intrauterine infusion (PRPI) 24 hours PO. Data showed a significant positive effect of PRPI on the chance to become pregnant in mares affected by Kenney I-II CDE. The overall 14 days PO pregnancy rate was 75%. Sixty-nine % of the overall pregnancies was achieved with the 1st PRPI, but an additional 31% was obtained with the 2nd PRPI at the...
Jaworska J, Ropka-Molik K, Kowalczyk-Zięba I, Boruszewska D, Wocławek-Potocka I, Siemieniuch M.Physiological parturition is characterized by sterile, inflammatory-like processes. During parturition, the placenta expresses various proinflammatory mediators, such as chemokines and IL-17. Nevertheless, inflammatory processes present in the parturient mare are poorly characterized. The aim of this study was to investigate the expression of selected chemokines and IL-17 in the allantochorion and the endometrium of mares that retained fetal membranes (RFM) and expelled them physiologically. We hypothesized that the expression of these mediators may be altered in the placenta of mares with RFM...
Tonekaboni FR, Narenjisani R, Staji H, Ahmadi-Hamedani M.This investigation aimed to compare the cell-free fetal DNA (cffDNA) plasma present in three trimesters of pregnancy in Torkaman pregnant mare. Peripheral blood samples of 32 pregnant mares in three trimesters of pregnancy were collected in tubes containing ethylenediaminetetraacetic acid at three time points. Circulating cffDNA was extracted from 3Â mL of maternal plasma. Using outer and inner primers, a conventional polymerase chain reaction was performed for the sex-determining region Y (SRY) gene present in the Y chromosome. Of the total 32 Torkaman pregnant mares, 24 were carrying male fe...
Kahler A, McGonnell IM, Smart H, Kowalski AA, Smith KC, Wathes DC, de Mestre AM.Early pregnancy loss (EPL) occurs in approximately 8% of equine pregnancies, although the aetiology is mostly unknown and embryonic/fetal morphological abnormalities associated with EPL are not defined. Objective: To compare the morphology of EPL to clinically normal embryos/fetuses and previously described embryonic/fetal developmental milestones. To identify morphological abnormalities associated with equine EPL. Methods: Observational case-control study. Methods: Embryos/fetuses were obtained from clinically normal Thoroughbred and pony pregnancies (n = 11) and following EPL from Thorough...
Hoppen HO.Chorionic gonadotrophins seem to be unique for primate and equid species. Unlike primates, the equine conceptus does not implant in the maternal uterine endometrium until around day 37 of pregnancy. At this time specialized cells of the trophoblast, organized in the embryonic girdle, invade the endometrium and become established in the endometrial stroma, forming the so-called endometrial cups. This migration of girdle cells is accompanied by their morphological transformation into large decidual-like cells and by the appearance of a gonadotrophic hormone in the mare's blood. There is convinci...
Zong E, Fan G.Generally speaking, the majority of F1 hybrids between the horse and donkey are sterile and do conform to the hypothesis of gametogenic breakdown. The results of our own research, nevertheless, lead us to conclude that there is variability in degree of sterility and fertility for both F1 and B1 individuals, with a gradual advance from sterility to fertility being seen. This is the subject we will discuss from the point of view of oestrus, ovulation, mating, pregnancy, spermatogenesis, endocrine activity, isozymes and karyotypic analysis in this paper.
Houpt KA, Eggleston A, Kunkle K, Houpt TR.Six pregnant mares were used to determine what level of water restriction causes physiological and/or behavioural changes indicative of stress. Nonlegume hay was fed ad libitum. During the first week of restriction, 5 l water/100 kg bwt was available, during the second week 4 l/100 kg bwt and, during the third week, 3 l/100 kg bwt. Ad libitum water intake was 6.9 l/100 kg bwt; at 3 l/100 kg bwt water intake was 42% of this. Daily hay intake fell significantly with increasing water restriction from 12.9 +/- 0.75 kg to 8.3 +/- 0.54 kg; bodyweight fell significantly for a total loss of 48.5 +/- 8...
Amann RP.Apparent fertility of a male or group of females is considered frequently by veterinarians or animal scientists. Unfortunately, concepts of experimental design and statistics impacting validity and interpretation of values for average pregnancy rate frequently are ignored. The magnitude of this problem was documented by examination of published papers; 51 of 67 (76%) were considered flawed for one or more reasons. The discussion considers why: (a) conclusions from most published fertility studies reporting no significant difference due to treatment(s) are suspect, because too few males and/or ...
Rambags BP, van Tol HT, van den Eng MM, Colenbrander B, Stout TA.Progesterone and oestrogen play essential roles in the maintenance of pregnancy in eutherian mammals and are thought to exert their effects on the developing conceptus indirectly, via the endometrium. In some species, early embryos have themselves been shown to express steroid receptors, thereby suggesting that reproductive steroids may also influence embryonic development directly. The aim of this study was to determine whether early intrauterine equine conceptuses express either the classical intracellular progesterone (PR) and oestrogen receptors (ERalpha and ERbeta) or the more recently ch...
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) ...
Ricketts SW, Alonso S.Paired endometrial biopsy samples were taken from 530 subfertile mares, before and after treatment (where indicated) and a period of sexual rest. Prognoses were made after each biopsy (Categories 1A-4A before treatment and Categories 1B-4B after treatment), using histopathological criteria similar to those described by Kenney and Doig (1986). Eighty-seven per cent of the mares were assigned to first biopsy prognosis Category 3A. The second biopsy prognosis produced a more even population distribution (10, 47, 40 and 3 per cent respectively for Category 1B, 2B, 3B and 4B mares). First biopsy Ca...
Robles M, Couturier-Tarrade A, Derisoud E, Geeverding A, Dubois C, Dahirel M, Aioun J, Prezelin A, Calvez J, Richard C, Wimel L, Chavatte-Palmer P.Foals born to primiparous mares are lighter and less mature than those born to multiparous dams. Factors driving this difference are not totally understood. Using 7 multiparous and 6 primiparous standardbred mares, we demonstrated that, in late gestation, primiparous mares were less insulin resistant compared to multiparous mares, and that their foals had reduced plasma amino-acid concentrations at birth compared to foals born to multiparous mares. Vascular development, as observed through structure and gene expression, and global DNA methylation were also reduced in primiparous placentas. Ano...
Kolm G, Klein D, Knapp E, Watanabe K, Walter I.Lactoferrin (LF) is an estrogen-regulated glycoprotein with well-described antibacterial and immunomodulatory properties. The present study is the first report on LF expression in horse endometrial specimens. Mares chosen for the study were either resistant or susceptible for persisting mating-induced endometritis (PMIE) during the natural ovulatory cycle and in early pregnancy. Our investigations included immunostaining for LF protein and CD18, a leukocyte marker, as neutrophils are a possible source for LF in the endometrium. Quantification of LF mRNA was performed by use of real-time RT-PCR...
Plotka ED, Eagle TC, Gaulke SJ, Tester JR, Siniff DB.Blood was collected from 486 feral horses of mixed sex and age classes captured from three wild horse management areas in Nevada and Oregon from December 1985 to February 1986. Males were significantly outnumbered by females in the Flanigan area, but both sexes were represented in approximately equal numbers in the Wassuk and Beaty's Butte areas. Hematology and chemistry values averaged 16.4 +/- 0.11, 46.3 +/- 0.28, 9.9 +/- 0.07, 6.9 +/- 0.10, 47.1 +/- 0.24, 16.6 +/- 0.09, 35.2 +/- 0.09, 10.4 +/- 0.14 and 23.4 +/- 0.25 for hemoglobin (HGB), hematocrit (HCT), red blood cells (RBC), white blood ...
Camozzato GC, Martinez MN, Bastos HBA, Fiala-Rechsteiner S, Meikle A, Jobim MIM, Gregory RM, Mattos RC.The aim of this study was to evaluate ultrastructural and histological changes in the endometrium on days 7, 10 and 13 post-ovulation in pregnant and cyclic mares. Mares were routinely examined by transrectal palpation and ultrasonographic examination of the reproductive tract until estrus was detected. In the first cycle, endometrial biopsies from 30 cyclic mares (Cyclic group) were collected on days 7, 10 and 13 post-ovulation. In the second cycle, the same mares were bred by a fertile stallion. At days 7, 10 and 13 post-ovulation intrauterine biopsies were collected. Immediately after sampl...
Gadella BM, Rathi R, Brouwers JF, Stout TA, Colenbrander B.During sexual reproduction, the sperm and oocyte must fuse before the production of a diploid zygote can proceed. In mammals such as equids, fusion depends critically on complex changes in the plasma membrane of the sperm and, not surprisingly, this membrane differs markedly from that of somatic cells. After leaving the testes, sperm cease to synthesize plasma membrane lipids or proteins, and vesicle-mediated transport stops. When the sperm reaches the female reproductive tract, it is activated by so-called capacitation factors that initiate a delicate reorientation and modification of molecul...
Legacki EL, Corbin CJ, Ball BA, Wynn M, Loux S, Stanley SD, Conley AJ.Mammalian pregnancies need progestogenic support and birth requires progestin withdrawal. The absence of progesterone in pregnant mares, and the progestogenic bioactivity of 5α-dihydroprogesterone (DHP), led us to reexamine progestin withdrawal at foaling. Systemic pregnane concentrations (DHP, allopregnanolone, pregnenolone, 5α-pregnane-3β, 20α-diol (3β,20αDHP), 20α-hydroxy-5α-dihydroprogesterone (20αDHP)) and progesterone) were monitored in mares for 10days before foaling (n=7) by liquid chromatography-mass spectrometry. The biopotency of dominant metabolites was assessed using luci...
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...
The proteins galectin-1 and Progesterone Induced Blocking Factor (PIBF) are present on human and murine trophoblast and are thought to influence both immunomodulation and trophoblast invasion. In equids, the invasive component of the placenta, the endometrial cups, stimulate maternal cell-mediated and humoral immune responses. It was therefore of interest to know if galectin-1 or PIBF could be immunolocalised to the invasive and/or non-invasive components of the equine placenta. Horse and mule (♀ horse X ♂ donkey) embryos and placental tissues between Days 12 and 124 of gestation were stai...
Gibson C, de Ruijter-Villani M, Rietveld J, Stout TAE.Maternally derived amino acids (AA) are essential for early conceptus development, and specific transporters enhance histotrophic AA content during early ruminant pregnancy. In the present study we investigated AA transporter expression in early equine conceptuses and endometrium, during normal pregnancy and after induction of embryo-uterus asynchrony. 'Normal' conceptuses and endometrium were recovered on Days 7, 14, 21 and 28 after ovulation. To investigate asynchrony, Day 8 embryos were transferred to recipient mares on Day 8 or Day 3, and conceptuses were recovered 6 or 11 days later. Endo...
Kydd JH, Case R, Winton C, MacRae S, Sharp E, Ricketts SL, Rash N, Newton JR.Identification of risk factors which are associated with severe clinical signs can assist in the management of disease outbreaks and indicate future research areas. Pregnancy loss during late gestation in the mare compromises welfare, reduces fecundity and has financial implications for horse owners. This retrospective study focussed on the identification of risk factors associated with pregnancy loss among 46 Thoroughbred mares on a single British stud farm, with some but not all losses involving equid herpesvirus-1 (EHV-1) infection. In a sub-group of 30 mares, association between pregnancy ...
Kindahl H, Knudsen O, Madej A, Edqvist LE.Blood samples from 4 mares during the late luteal phase, oestrus, early pregnancy and up to about 150 days of gestation were analysed for 15-keto-13,14-dihydroprostaglandin F-2 alpha (PGFM), progesterone, PMSG and oestrone sulphate by radioimmunoassays. During the late luteal phase, at the time of corpus luteum regression and decreasing progesterone levels, PGFM peaks were recorded. During early pregnancy (i.e. from mating and up to about Day 30) no such peaks were detected. After mating the progesterone levels increased and remained high throughout the observation period. During the oestrous ...
Tijjani AO, Junaidu AU, Salihu MD, Farouq AA, Faleke OO, Adamu SG, Musa HI, Hambali IU.A cross-sectional epidemiological study was conducted to determine seroprevalence and risk factors influencing the presence of Brucella antibodies in donkeys of Borno State, north-eastern Nigeria. The study aimed at providing baseline information that may be used in planning a control policy against equine brucellosis. Blood samples were collected from 601 donkeys, comprised of 374 males and 227 females from the six agricultural zones of the state between March 2013 and September 2014. The sera obtained were tested for Brucella antibodies using Rose Bengal plate test (RBPT) and competitive enz...
Betteridge KJ.Carl Hartman's title of 47 years ago is invoked in tribute to his first recovery of a bovine embryo 30 years before that, and his legacy of an emphasis on the value of descriptive and comparative studies in reproductive biology. The horse's qualification as a farm animal has waned since those times but, in a conference understandably dominated by research in ruminants and pigs, there are lessons to be learned from some peculiarities of equine embryonic development. Morphological and physiological features of the conceptus and its interaction with its environment during the first month of pregn...
Allen WR, Wilsher S, Stewart F, Stewart F, Ousey J, Ousey J, Fowden A.Within-breed artificial insemination and between-breed embryo transfer were carried out in small pony (P) and large Thoroughbred (Tb) mares to create 4 types of horse pregnancy in which the fetus experienced spatial and nutritional deprivation (Tb-in-P; n=8), luxury (P-in-Tb; n=7) or normality (Tb-in-Tb; n=7 and P-in-P; n=7) in utero. Measurement of equine chorionic gonadotrophin (eCG), total conjugated oestrogens and progestagen concentrations in serial peripheral serum samples recovered from all the mares throughout gestation showed that the amount of eCG produced during the first half of ge...
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...
Bresgen C, Lämmer M, Wagner B, Osterrieder N, Damiani AM.Equine herpesvirus type 1 and type 4 (EHV-1 and EHV-4) cause infections of horses worldwide. While both EHV-1 and EHV-4 cause respiratory disease, abortion and myeloencephalopathy are observed after infection with EHV-1 in the vast majority of cases. Disease control is achieved by hygiene measures that include immunization with either inactivated or modified live virus (MLV) vaccine preparations. We here compared the efficacy of commercially available vaccines, an EHV-1/EHV-4 inactivated combination and an MLV vaccine, with respect to induction of humoral responses and protection of clinical d...
Schönbom H, Kassens A, Hopster-Iversen C, Klewitz J, Piechotta M, Martinsson G, Kißler A, Burger D, Sieme H.Pregnancy diagnostics in equine reproduction are routinely performed using transrectal ultrasonography, although it is also possible to visualize the fetus by transabdominal ultrasound examinations from the 90th day of gestation onward. We hypothesized that ultrasound examinations may stress the mare and that the gestational stage status and lactation may influence the mare's stress reaction. To investigate the stress reaction, 25 thoroughbred mares of different age, pregnancy and lactational status underwent a transrectal examination. In pregnant mares, an additional transabdominal examinatio...
Squires EL, McCue PM, Vanderwall D.The use of embryo transfer in the horse has increased steadily over the past two decades. However, several unique biological features as well as technical problems have limited its widespread use in the horse as compared with that in the cattle industry. Factors that affect embryo recovery include the day of recovery, number of ovulations, age of the donor and the quality of sire's semen. Generally, embryo recoveries are performed 7 or 8 d after ovulation unless the embryos are to be frozen, in which case recovery is performed 6 d after ovulation. Most embryos are recovered from single-ovulati...
Miglio A, Morelli C, Maresca C, Felici A, Di Gianbattista A, Antognoni MT.Serum protein electrophoresis (SPE) reference intervals (RIs) have been evaluated in different horses, but no specific values are shown for equine breeds as previously described in other species (dogs, cats), and no studies have been performed on SPE in draft horses. Objective: This study aimed to determine RIs for SPE in heavy draft horses (Italian Heavy Draft Horse-IHDH) living in central Italy. A comparison between different physiologic states (pregnancy and no pregnancy) and ages (foals and adults) was executed. Methods: Blood samples were collected from 215 apparently healthy horses (mare...
Raeside JI, Christie HL, Renaud RL, Waelchli RO, Betteridge KJ.Because estradiol (E(2)) production by the early equine conceptus is considered crucial to the establishment of pregnancy, the amounts of E(2), estrone (E(1)), and their sulfates (E(2)S, E(1)S) were measured by RIA in yolk-sac fluid of 63 conceptuses collected by transcervical lavage over the period of 11-26 days after ovulation. Amounts increased significantly with age of conceptus, especially for E(1)S. Then, the metabolism of E(2), which may be highly relevant for its action, was examined in the conceptus and endometrium over the period when the conceptus ceases to migrate within the uterus...
Lagneaux D, Huhtinen M, Koskinen E, Palmer E.Equine embryos recovered on Day 6 after ovulation were cooled to +4 degrees C, or frozen with AFP alone or together with glycerol. Twenty embryos (140-200 microm in diameter) were randomly assigned to 6 treatment groups. In the first 3 groups, the embryos were cooled from room temperature to +4 degrees C at a rate of 3 degrees C/min and warmed again at a rate of 32 degrees C/min in a programmable freezer. In the second 3 groups, the embryos were frozen using a standard protocol, stored in liquid nitrogen for 5-7 days and then thawed in a 37 degrees C waterbath. After cooling/warming or freezin...
Swegen A.Maternal recognition of pregnancy (MRP) is a process by which an early conceptus signals its presence to the maternal system and prevents the lysis of the corpus luteum, thus ensuring a maternal milieu supportive of pregnancy continuation. It is a fundamental aspect of reproductive biology, yet in the horse, the mechanism underlying MRP remains unknown. This review seeks to address some of the controversies surrounding the evidence and theories of MRP in the equine species, such as the idea that the horse does not conform to the MRP paradigm established in other species or that equine MRP invo...
