Reproduction in horses encompasses the biological processes and mechanisms involved in the breeding and development of equine offspring. This includes the study of reproductive anatomy, physiology, and endocrinology in both mares and stallions. Key areas of interest include the estrous cycle, ovulation, conception, gestation, and parturition. Researchers also examine factors influencing fertility, reproductive technologies such as artificial insemination and embryo transfer, and management practices that impact reproductive success. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological, genetic, and environmental aspects of equine reproduction.
Frayne J, Stokes CR.The quantity and distribution of MHC Class II positive cells and T cells in the equine endometrium was investigated throughout the oestrous cycle. Significantly more MHC Class II positive cells were detected in the stratum compactum and stratum spongiosum of endometria from naturally cycling mares during the follicular than during the luteal phase of the oestrous cycle. Significantly more T cells were also detected in the stratum compactum, but not stratum spongiosum, of these mares during the follicular phase. Furthermore, there was a marked increase in the number of MHC Class II positive cel...
Sertich PL, Reef VB, Oristaglio-Turner RM, Habecker PL, Maxson AD.A multiparous pregnant Welsh Pony mare was examined because of anorexia, dyspnea, and a large abdomen. Ultrasonography of the uterus revealed an excessive amount of amniotic fluid surrounding the fetus. Transabdominal ultrasonography permitted differentiation of hydrops amnii from hydrops allantois. The mare aborted a 7-month-old fetus with brachygnathia and a large, edematous umbilical cord. Hydrops amnii, an excessive accumulation of amniotic fluid in the amniotic cavity, is most commonly reported in cattle and sheep.
Mäkelä O, Gustavsson I, Hollmén T.Chromosomal analysis is not a routine examination in equine
practice. It is indicated, however, in infertile or subfertile
mares with small, inactive ovaries (Chandley et a/. 1975;
Power 1986).
The most commonly reported abnormalities in mares
concern sex chromosomes such as 63,XO and mosaic
63,XO/64,XX giving sterile mares and 64,XY resulting in
gonadal dysgenesis, sex reversal and testicular feminisation
(Power 1990). The phenotypic manifestations of a horse with
these karyotypic abnormalities are usually quite mild
compared with the corresponding abnormalities in man. These
mild ...
Böse R, Peymann B.From Babesia caballi in vitro cultures a preparation of 100% infected erythrocytes was obtained. From this, B. caballi antigens were extracted with the detergent 3-[(3-Cholamidopropyl)-dimethylammonio]-1-propane-sulfonate (CHAPS) and used as ELISA antigens. A control antigen of normal erythrocytes from the same donor horse was prepared in an identical manner. The ELISA and Western blot were validated by testing of sera from horses experimentally infected with B. caballi or B. equi or not infected with Babesia spp. ELISA and Western blot results were compared with those obtained by the immunofl...
Rodríguez H, Bustos-Obregón E.Epididymal sperm maturation in the stallion was analysed using eight epididymides and deferent ducts from healthy animals. Samples were obtained in June-July and October-November (resting and breeding periods, respectively). Epididymides were divided into head, body and tail. Sperm samples were submitted to a routine seminogram, chromatin decondensation test (Lung, 1972) and sperm velocity determination (Makler, 1980). Results demonstrate that stallion spermatozoa achieve maturation in the transition between the head and body of the epididymis as revealed by chromatin decondensation. Objective...
Willis P, Sekhar KN, Brooks P, Fayrer-Hosken RA.To characterize further the events involved in fertilization and early embryonic development in the mare, effect of the estrous cycle on oviductal fluid proteins was investigated. Five mares had indwelling cannulas placed in their oviducts so that fluid could be collected throughout the estrous cycle. Daily fluid volumes were recorded and mares were monitored for signs of standing estrus. Oviductal fluid samples were pooled across mares according to stage of cycle (either estrus or nonestrus) for further analysis. Two-dimensional polyacrylamide gel electrophoresis (PAGE) was used to determine ...
Pirhonen A, Linnala-Kankkunen A, Mäenpää PH.Protamines isolated from ejaculated human, stallion, bull, boar, and ram spermatozoa were subjected to phosphoserine conversion reaction and protein sequencing. Phosphoserines were detected as S-ethylcysteines. Endogenously phosphorylated protamines have previously been found only in ejaculated human sperm. In this study, we demonstrate that ejaculated sperm from other species also contain protamines phosphorylated at serine residues. In P1-protamines, the endogenously phosphorylated serines were located at the N-terminal region in all species studied, whereas in major forms of human and stall...
Parlevliet JM, Kemp B, Colenbrander B.The semen characteristics and testicular size of 398 3-year-old maiden Dutch Warmblood stallions were studied during February and March. Mean values (+/- SD) of age (1030 +/- 88 days) and testicular size (9.8 +/- 0.9 cm) of the maiden stallions were determined as well as the following semen characteristics (mean of two ejaculates, taken 1 h apart): volume (65 +/- 26 ml), sperm concentration (2.061 +/- 1.685 x 10(8) ml-1), total number of spermatozoa (1.129 +/- 0.71 x 10(10)), percentage of progressively motile spermatozoa (68 +/- 9%), percentage of live spermatozoa with normal morphology (66 +...
Johnson JU, Oxender WD, Berkhoff HA.Effect of estrogen (E2) and progesterone (P4) on uterine antibacterial activity and immunoglobulin concentrations in mares was studied. In 2 in vitro experiments, 6 mixed-breed mares were ovariectomized, and uterine fluid and blood serum were analyzed. Antibacterial assay methods were used to determine inhibitory effects on Streptococcus zooepidemicus of uterine fluid samples collected on days 3, 5, and 8, and serum obtained on day 8 of treatment. Single radial immunodiffusion methods were used to quantify amounts of IgA and IgG in uterine fluid and serum on days 3, 5, 8, and 14 of treatment. ...
Oriol JG.In most domestic animals, the zona pellucida is the outermost extracellular layer that covers the blastocyst before implantation. However, in the horse, an acellular membrane, the capsule, replaces the zona pellucida and envelops the developing conceptus during the 2nd and 3rd weeks of gestation. Although this structure was first described by Bonnet in 1889, it received little attention until the 1970s when its rediscovery by Marrable and Flood (1975) led to a series of reports (see review by Betteridge 1989). Nevertheless, until recently the structure, origin, and function of the capsule have...
Sertich PL.The events surrounding parturition are well orchestrated, and normal delivery of a foal is an explosive, rapidly occurring event. Any aberration may jeopardize the pregnancy and cause clinical complications. This article discusses problems associated with the periparturient period that require immediate attention.
Hough SR, Parks JE.Platelet-activating factor (PAF) acetylhydrolase, which inactivates PAF, has been detected in human and bovine seminal plasma and may represent a mechanism for regulating sperm-derived PAF. This study was designed to characterize further PAF acetylhydrolase in seminal plasma from domestic animal species. Sperm-free seminal plasma from the bull, stallion, rabbit, and rooster was assayed for acetylhydrolase activity based on the release of [3H]acetate from PAF. As reported previously for bull seminal plasma, activity in stallion, rabbit, and rooster seminal plasma was linear with both time and p...
Vaala WE, Sertich PL.Perinatal death accounts for a large percentage of foal mortality. The most serious threats to perinatal survival remain septicemia, hypoxia, and dysmaturity. Topics discussed in this article include biochemical indices of fetoplacental function and evaluation and management of the high-risk mare.
Vivrette S.The endocrinology of late gestation and parturition in the mare has been described, but unlike other domestic animal species, the factors that initiate parturition in the mare have not been elucidated. In contrast to ruminant species, maternal estrogen and progesterone concentrations do not change markedly, and a well-defined fetal cortisol surge is not observed just prior to parturition in the mare. Parturition is associated with large increases in prostaglandin and oxytocin concentrations, which induce uterine contractions and delivery of the foal. There are many methods of inducing parturit...
Holyoak GR, Little TV, Vernon M, McCollum WH, Timoney PJ.Correlation between serum testosterone concentration and morphometric findings from ultrasonography of the accessory sex glands in peripubertal colts was investigated during pubertal development. Nineteen colts of initial age ranging from 5 to 12 months were monitored over a 13-month period. Serum testosterone concentration was determined on a biweekly basis, and accessory sex gland development was ultrasonographically monitored once a month. Notwithstanding individual variation, there was significant correlation (r = 0.913; P < 0.01) between increasing serum testosterone concentration and ...
McClure JJ, Koch C, Traub-Dargatz J.A red cell antigen of donkeys and mules was identified using antibodies in serum from a mare which produced a mule foal affected with neonatal isoerythrolysis (NI). Subsequently antibodies with similar activity were identified in the sera of other mares which had produced mule foals and were produced by immunization of horses with blood from donkeys. The antigen detected by these antibodies does not correspond to any recognized horse red cell alloantigen. This may be a xenoantigen since all donkeys (and mules) tested have shared this antigen and all horses tested have lacked the antigen. The r...
Hess-Dudan F, Vacher PY, Bruckmaier RM, Weishaupt MA, Burger D, Blum JW.Concentration of (total) globulin was relatively stable in blood plasma of mares, but rapidly decreased in colostrum to very low levels within 2 days after parturition. In foals, after intake of the first colostrum, globulin increased within 1 day in blood plasma, but remained at lower concentrations than those measured in mare plasma. Concentrations of immunoreactive insulin (iI) were high during the first 2 months of lactation in blood plasma of mares and then decreased, were high in first colostrum and then decreased drastically, and remained at low concentrations up to weaning in blood of ...
LeBlanc MM, Neuwirth L, Asbury AC, Tran T, Mauragis D, Klapstein E.The percentage of Technetium 99m-albumin colloid (99mTc-microAA), a radiocolloid, cleared from the uterine lumen within 4 h of intrauterine infusion, was measured in 15 mares during 2 consecutive cycles, on Day 3 of oestrus and 48 h after ovulation. Four nulliparous (Group 1) and 4 multiparous (Group 2) mares were classified as resistant and the remaining 7 multiparous mares were classified as susceptible (Group 3) to endometritis. Mares in Groups 1 and 2 cleared more 99mTc-microAA from their uteri than did mares in Group 3 during oestrus (P < 0.01) and 48 h after ovulation (P 50% of the c...
Teuscher C, Kenney RM, Cummings MR, Catten M.In this study, 2 stallions were immunised with their own spermatozoa to ascertain whether an antisperm autoantibody response could be mounted. The results demonstrated that the stallion can recognise and respond to sperm autoantigens by producing circulating antisperm antibodies, primarily of the IgG class. Such autoantibodies appeared 2-4 weeks after inoculation and persisted for 6-20 weeks. Immunochemical characterisation by western blot identified two major sperm autoantigens, with molecular weights of 70 kD and 62 kD. Control pony stallions immunised with adjuvants alone failed to exhibit ...
Pemberton AD, John HA, Ricketts SW, Rossdale PD, Scott AM.Failure to inhibit proteinases can lead to excessive tissue damage. The possibility that the severity of endometritis in Thoroughbred mares correlates with the haplotypes of plasma alpha 1-proteinase inhibitor (alpha 1-PI) expressed was investigated in two groups of mares. In mares with pyometritis before treatment, the frequency of the N haplotype, which is already high in the Thoroughbred population, was significantly increased when compared with that in a large published population. In mares with acute endometritis which persisted after treatment followed by sexual rest, the absence of S an...
Vos PL, van der Schans A, de Wit AA, Bevers MM, Willemse AH, Dieleman SJ.Normally cyclic heifers (n = 34) received 2500 iu pregnant mares' serum gonadotrophin (PMSG) i.m. at day 10 of oestrus, and 15 mg prostaglandin (PG) i.m. at day 12. Thereafter, a monoclonal antibody against PMSG was administered i.v. before (n = 24), at (n = 6) or shortly after (n = 4) the preovulatory LH surge. Peripheral blood concentrations of LH and oestradiol were compared; follicular development was monitored by daily ultrasound scanning; and the numbers of preovulatory-sized follicles and ovulations were counted 96 h after injection of PG following death. Anti-PMSG treatment before the ...
Kotilainen T, Huhtinen M, Katila T.The objective of this study was to investigate the inflammatory reaction induced in the equine uterus by insemination with fresh and frozen semen. Eleven groups (6 to 8 mares per group) were studied during 2 breeding seasons. The mares were inseminated using raw semen, frozen semen, extended fresh and frozen semen, concentrated fresh semen, seminal plasma and seminal extenders only. One group was bred naturally. Six hours after insemination, the uteri were flushed with 50 ml of phosphate-buffered saline (PBS). Seventeen out of 104 samples (16%) exhibited slight bacterial growth. Neutrophil con...
Ginther OJ, Baucus KL, Bergfelt DR.The ovaries of periparturient pony mares (n=9 to 16 parturitions per month for January to April) were scanned ultrasonically on the day of parturition, while those of postpartum and control mares (n=12) were examined at least twice weekly. Four mares had apparent lactational anovulation (incidence, 7%) that corrected spontaneously (1 mare) or within 14 d after the weaning of foals on August 10 (3 mares). All but 2 of the postpartum ovulations occurred after April 29; that is, parturition did not effectively stimulate ovulation in ponies foaling during the anovulatory season. Mean diameter of t...
McClure JR, Chapman MR, Klei TR.Since 1978, 20 surgical implantations of either Strongylus vulgaris or Strongylus edentatus have been performed in our laboratory for the purpose of obtaining single species cultures of these parasites. Following surgical implantation peak EPG values of 13-327 (S. vulgaris) and 363-1284 (S. edentatus) generally occurred during the first 3 weeks post-implantation. Duration of infections was as long as 5 years. Successful outcome of such surgeries appears to be related to the total number of parasites used (> or = 38) and the ratio of female to male worms implanted (1:1 or 2:1).
Irvine CH, Alexander SL.Conflicting views exist on the mode of gonadotrophin-releasing hormone (GnRH) secretion during the ovulatory LH surge and the relative importance of changes in pituitary responsiveness to GnRH in generating the LH surge. This disagreement may stem from species differences and/or methodological problems. To provide data on the exact relationship between GnRH and gonadotrophin secretion during the spontaneous LH surge, we collected pituitary venous (PV) blood every 30 s for 3-4 h from eight mares and then assayed GnRH (in six of the mares), FSH and LH. Jugular blood was also collected from twelv...
Bostedt H, Lehmann B.By means of clinical and analytical procedures (enzyme immuno assay for progesterone with microtiterplate method) the ovarian activity from 27 mares was tested over a period of several weeks. The measurement of the progesterone level to determine the time of ovulation was proved as suitable in the period of 1-2 days after ovulation. In normocyclic mares (n = 17) a different development of the progesterone profile was detected, so that an insufficient development of the corpus luteum (35%) could be considered. By means of continuous measurement of progesterone (> or = 30 days) six of ten mares ...
Elshalofy A, Wagener K, Weber K, Blanco M, Bauersachs S, Bollwein H.This study aimed to investigate the susceptibility to persistent breeding-induced endometritis (PBIE). Cytobrush samples were collected from 81 broodmares 1-3 days before artificial insemination (AI). Susceptibility to PBIE was evaluated by the presence of ≥ 2 cm of intrauterine fluid 24 h after AI, besides the fertility was determined by a sonographic pregnancy diagnosis 2 weeks after ovulation. RNA expressions were compared between susceptible non-pregnant (SNP) mares (n=9) and resistant pregnant (RP) mares (n=9) as well as between susceptible pregnant (SP) mares (n=9) and susceptible non-...
Otzen H, Sieme H, Oldenhof H, Kassens A, Ertmer F, Rode K, Müller K, Klose K, Rohn K, Schoon HA, Meinecke B.The aim of this study was to evaluate the uterine blood supply and endometrial vessel architecture, during the equine estrous cycle. Narrow Band Imaging (NBI) hysteroscopy was used for evaluating changes in the endometrial vasculature during the estrous cycle [six mares, d 0 (representing the day of ovulation), d 6 and 11 in four locations]. In addition, endometrial biopsy samples were used for immunodetection of markers for angiogenesis (Vascular Endothelial Growth Factor A, its receptor 2, as well as angiopoietin-2 and its receptor-tyrosine-kinase Tie2) during the estrous cycle (three mares,...
Carluccio A, Contri A, Tosi U, De Amicis I, De Fanti C.To determine survival rate, complications, and short-term fertility rate after fetotomy in mares. Methods: Retrospective study. Methods: 72 mares with severe dystocia. Methods: Records from 1991 to 2005 were searched for mares with dystocia in which a fetotomy was performed. Data relating to presentation and position of foals; survival rate, complications, and short-term fertility rate in mares; and 45-day pregnancy rate in mares bred 2 to 3 months after fetotomy were recorded. Results: Anterior fetal presentation was detected for 54 of 72 (75%) mares, posterior presentation was detected for 1...
Schrammel N, Deichsel K, Aurich J, Aurich C.Horses are seasonal breeders, and robust breeds may exhibit a winter hypometabolism when kept under semiferal conditions. In this study, we analyzed the effects of artificial long days on rectal temperature, heart rate, heart rate variability, hematology, coat changes, semen parameters, and plasma testosterone concentrations in Shetland stallions stabled overnight and assigned to a control group (CON, n = 9) kept under natural photoperiod, and a treatment group exposed to a long-day light program from 15 December to 20 March (AL, n = 9). During the 8-month study, rectal temperature, heart rate...
López ML, Olea N, Retamal CA.Freeze-fracture replicas of stallion spermatozoa, collected from the proximal caput, corpus and cauda epididymides regions, were analyzed by electron microscopy to explore the distribution and density of intramembrane particles (IMP). Conspicuous differences in density and arrangement of the IMP were observed in the different topographical domains of mature and immature spermatozoa. A reduction of IMP, especially remarkable in the post-acrosomal domain, was observed in mature epididymal spermatozoa when compared with samples collected from ductuli efferentes. Some structural species-specific d...
Amann RP, Cristanelli MJ, Squires EL.Motility and fertility of frozen-thawed semen differs greatly amongst stallions. Differences in seminal plasma might be one cause of this variation. For 8 ejaculates from each of 17 stallions, seminal plasma was saved at -20 degrees C and spermatozoa were cryopreserved. Based on post-thaw sperm motility, seminal plasma samples from 7 stallions (2 good, 3 variable, 2 poor sperm motility) were selected for measurement of electrolytes, protein content and analysis by sodium dodecylsulphate gel electrophoresis (10% gel, Coomassie blue stain). Variation in seminal plasma was significant (P less tha...
Thomas PG, Ball BA, Ignotz GG, Dobrinski I, Parks JE, Currie WB.Before fertilization, equine spermatozoa adhere to oviduct epithelial cells (OEC) of the mare. The biochemical basis for this adhesion has not been determined. Our objective was to produce an antiserum to block this interaction. Ejaculated spermatozoa were subjected to nitrogen cavitation and spermatozoal plasma membranes enriched by sucrose density gradient centrifugation; membrane enrichment was confirmed by comparative alkaline phosphatase analysis, electron microscopy, and one- and two-dimensional PAGE. Periacrosomal plasma membrane was used as an immunogen for the production of an antiser...
Zhou H, Liu C, Wang W.This study was conducted to reconstruct heterogeneous embryos using equine skin fibroblast cells as donor karyoplasts and the bovine oocytes as recipient cytoplast for investigating the reprogramming of equine somatic cell nuclear in bovine oocyte cytoplasm and the developmental potential of the reconstructed embryos. Adult horse skin fibroblast cells serum-starved were used as donor somatic cells. Bovine oocytes matured in vitro were employed as recipient cytoplasts. The fusion of fibroblast cells into recipient cytoplasm was induced by electofusion. The fused eggs were activated by inomycin ...
Aurich C, Budik S.Although the horse is a seasonal breeding species, a considerable number of mares continue to cycle throughout autumn and winter. Slower equine embryo growth during the non-breeding season has been hypothesized, and because smaller embryo size is beneficial for cryopreservation, embryo collection outside the breeding season could be an interesting approach for the production of frozen horse embryos. In the present retrospective study, we have therefore analysed embryo recovery rates and conceptus size in mares (n = 30) throughout the year. Conceptus diameter was either size determined after co...
Taverne MA.For the past few years, two-dimensional diagnostic ultrasound methods have become available to veterinary medicine. In particular, linear-array real-time ultrasound would appear to be a very suitable diagnostic tool in the examination of the female genital organs of domestic mammals. The principles of this technique and the equipment available are described, and particular attention is paid to the method by which a diagnosis of pregnancy may be established in various animal species. In dogs and goats shaving will have to be done before the sound-transmitting/receiving transducer can be placed ...
Ginther OJ, Jacob JC, Gastal MO, Gastal EL, Beg MA.Ablation of follicles > or = 6 mm in diameter and treatment with PGF2alpha 10 days after ovulation were used to induce the development of ovulatory waves. Comparisons were made between induced waves with one (33 waves, 72%) and multiple (13 waves, 28%) ovulatory follicles. Diameter deviation was defined as the separation of follicles into dominant and subordinate categories. Multiple ovulatory follicles were preceded by more (p or = 20 mm at the beginning of deviation, higher LH preceding deviation (approached significance, p < 0.08), lower (p < 0.05) concentrations of FSH on the day...
Peippo J, Huhtinen M, Kotilainen T.A rapid and reliable method for sex determination of preimplantation-stage equine embryos has not been available. The aim of the present study was to find an enzyme which would distinguish sexes in the horse by finding a polymorphic restriction site between the ZFY and ZFX homologues amplified by the polymerase chain reaction (PCR). Altogether, 38 different restriction enzymes were tested using female and male DNA extracted from blood. The primers used for amplification were selected from conserved sequences between human ZFY and ZFX genes and mouse Zfy-1 and Zfy-2 genes. Nine enzymes cut the ...
Howden KJ.A Thoroughbred mare was presented for stallion-like behavior. Reproductive and ultrasonographic evaluation, testosterone assays, and karyotyping confirmed a diagnosis of androgen insensitivity syndrome (64, XY--testicular feminization). Surgery to remove abdominal testicles was successful in alleviating the behavioral abnormality. This condition is discussed with reference to the current literature. Une jument Thoroughbred a été présentée parce qu’elle avait un comportement d’étalon. Une évaluation reproductrice et échographique, des dosages de testostérone et un caryotypage ont c...
Padilla AW, Tobback C, Foote RH.A method for preparing stored unfrozen stallion spermatozoa for the zona-free hamster oocyte penetration test (HOPT) and a subsequent comparison of fresh and stored sperm by the HOPT were evaluated. In Experiment 1, sperm from 4 stallion ejaculates, cooled to 4 degrees C and stored for 24 h, were treated with 60, 90 and 120 microM of dilauroylphosphatidyl-choline (PC12) liposomes to initiate the acrosome reaction. The percentage of motile and acrosome-reacted (AR) sperm were recorded after 8, 15 and 30 min of incubation at 39 degrees C, by automated image analysis. Liposome concentration did n...
van Loon JP, van Oostrom H, Doornenbal A, Hellebrekers LJ.There is a need for objective evaluation and quantification of the efficacy of analgesic drugs and analgesic techniques in horses. Objective: To determine whether lumbosacral spinal cord somatosensory evoked potentials (SSEP) can be a useful and reliable tool to assess nociception in equines. Methods: SSEPs and electromyograms (EMG) from the epaxial muscles were recorded simultaneously, following electrical stimulation applied to the distal hindlimb in lightly anaesthetised Shetland ponies (n=7). In order to validate the model, the effect of increasing stimulus intensity was documented and the...
Consuegra C, Crespo F, Dorado J, Ortiz I, Diaz-Jimenez M, Pereira B, Hidalgo M.Vitrification of sperm is based on high-speed freezing by direct exposure to liquid nitrogen using non-permeable cryoprotectants, mainly disaccharides; yet, the concentration of cryoprotectants has a species-specific effect on the sperm cell. The aim of this study was to assess different sucrose concentrations for stallion sperm vitrification. Semen samples (n = 9) were collected from three stallions, centrifuged and resuspended to a concentration of 50 × 10 sperm/ml in a base extender (INRA96 + 1% of bovine serum albumin) with three different sucrose concentrations (Molar): 20 mM (S...
Davison LA, McManus CJ, Fitzgerald BP.In the mare, endogenous opioids have been implicated in the suppression of gonadotropin secretion during seasonal anestrus (AN). The present study tested whether continuation of reproductive activity during the nonbreeding season (NBS) reflects the absence of a seasonal shift in opioid tone compared to what occurs in AN mares. During the NBS, 11 AN and 8 luteal-phase mares received 0.1, 0.05, 0. 025 mg/kg naloxone (NAL) or vehicle on alternate days. Whereas cycling mares responded to all dosages of NAL, AN mares responded only to the higher dosages for FSH, and LH failed to increase at any dos...
Gao Y, Hannan MA, Murata K, Rajabi-Toustani R, Nambo Y.Equine-Assisted Therapy (EAT) is gaining popularity. Ultrasound examination is used to decrease the abortion rate in horses. In this study, to monitor fetal well-being throughout the gestation for EAT, we measured fetal heart rate (FHR), fetal eye orbit (FEO), fetal gonad length (FGL), fetal kidney length (FKL), and the combined thickness of the uterus and placenta (CTUP) by ultrasonography in pony mares. Additionally, we measured the plasma progesterone (P4) and estradiol (E2) concentrations in pregnant horses using enzyme immunoassay. The FGL peaked at week 32 and then decreased to term, and...
Köhne M, Ille N, Erber R, Adib Razavi MS, Walter I, Aurich C.Progestin concentration in plasma during the early luteal phase is crucial for endometrial function and conceptus development. We hypothesized that periovulatory gonadotrophin treatment via support of luteal function affects endometrial gene expression in horses. Effect of age was analyzed as well. Shetland mares (n = 8, age 4-25 years) were assigned to the following treatments during five consecutive cycles in alternating order following a cross-over design: treatment hCG/-: preovulatory injection of hCG, but no gonadotrophin injection at detection of ovulation, treatment -/hCG: no preovulat...
Shen Y, Ren H, Davshilt T, Tian S, Wang X, Yi M, Ulaangerel T, Li B, Dugarjav M, Bou G.During equine early gestation, trophectoderm forms chorion tissue, which is composed of two parts that one is covering allantoin, called allantochorion (AC) and another is covering yolk sac, which here we call vitelline-chorion (VC). Given that little is known about the equine trophoblast-derived chorion differentiation at an early stage, we first compared the transcriptome of AC and VC of day 30 equine conceptus based on RNA-sequencing. As a result, we found that compared to VC, there are 484 DEGs, including 305 up- and 179 down-regulated genes in AC. GO and KEGG analysis indicated that up-re...
Gastal EL, Gastal MO, Donadeu FX, Acosta TJ, Beg MA, Ginther OJ.Diameter of the preovulatory follicle, plasma concentrations of LH and estradiol, and vascularization of the follicle wall, based on color-Doppler signals, were characterized in 40 pony mares for 6 days preceding ovulation (Days -6 to -1; preovulatory period). Comparisons between the preovulatory periods preceding the first compared with a later ovulation during the year were used to study the relationships between LH and estradiol and between vascularization and estradiol. Diameter of the preovulatory follicle was greater (P<0.02) and concentration of LH was less (P<0.02) during the fir...
Shen Y, Ulaangerel T, Ren H, Davshilt T, Yi M, Li X, Xing J, Du M, Bai D, Dugarjav M, Bou G.The follicular fluid and oviduct fluid play major roles in oocyte maturation, sperm activation, and fertilization. To better understand the physiological environments for equine oocyte maturation and fertilization, here we conducted the proteome analysis and comparison on follicular fluids and oviduct fluids from the ovulatory side and the anovulatory side. The results showed that there is no significant difference between two side oviduct fluids, but a total of 71 differential abundance proteins (DAPs) were identified between two side follicular fluids, of which 9 are up-regulated and 62 are ...
Lopes Ede P, Siqueira JB, Pinho RO, Guimarães JD, Rocha AN, de Carvalho GR, Torres CA.The objective of this study is to evaluate the reproductive efficiency in donors and recipient Mangalarga Marchador mares in commercial programmes of embryo transfer (ET) and the effects of some reproductive characteristics and ET methodology on conception rates in the recipient mares. A total of 1140 flushing procedures were performed and 830 embryos (72.8%) were recovered. There were no differences between the rates of embryonic recovery in the different breeding seasons (p > 0.05) and 92.8% of the recovered embryos were 8-9 days old. There was no difference in the embryonic recovery regardi...
Vitte A, Rossignol F, Mespoulhes-Rivière C, Lechartier A, Röecken M.To report a combination of standing laparoscopic technique for intra-abdominal dissection of the mesovarial pedicle followed by a limited ventral median celiotomy under general anesthesia for removal of enlarged ovaries in mares. Methods: Case series. Methods: Mares (n = 20) aged 3-22 years with unilateral enlarged ovaries. Methods: Enlarged ovaries were confirmed by transrectal palpation and ultrasonography. After sedation, 3 laparoscopic portals were made in the paralumbar fossa. The mesovarium was desensitized and dissected using a vessel sealing device, and the ovary was left free in t...
Gao Y, Yoshida S, Takeyama A, Tagami M, Rajabi-Toustani R, Tsogtgerel M, Nambo Y.Ultrasound examination during late gestation is one of the best methods for monitoring potential pregnancy risks. Enlarged bladder is a urological disorder rarely observed in equine fetuses. This clinical case report aimed to present a case illustrating the development of equine fetal enlarged bladder using transabdominal ultrasound examinations and maternal hormone evaluation during gestation. An 8-year-old Hokkaido native pony was impregnated by embryo transfer, and at 215 days of gestation, abnormalities of the fetal bladder were detected. The bladder volume increased with gestational age, ...
Guimarães T, Lopes G, Ferreira P, Leal I, Rocha A.Cryopreservation of epididymal spermatozoa is a useful tool to preserve genetic material of valuable stallions after emergency castration or unexpected death. For that, testicles and epididymides are generally sent refrigerated to the laboratory. Collection of epididymal spermatozoa is a simple procedure that reduces the volume of the material to be shipped, and may improve the quality of the chilled epididymal sperm cells. In the present study we compared the characteristics of frozen/thawed epididymal spermatozoa after refrigeration of the epididymis or after direct refrigeration of the exte...
Bugno-Poniewierska M, Kij-Mitka B, Podstawski Z, Długosz B, Lasek O, Mrowiec P, Tischner M.The use of frozen semen lowers the risk of disease transmission, eliminates geographical limitations and supports the implementation of genetic resource protection programs. However, due to the very rare use of frozen semen from Hutsul stallions, their genetic material is not secured in sperm banks, and very little information is available about their semen, including its suitability for cryopreservation, and sperm survival rates after thawing. The aim of this study was to analyse basic parameters such as sperm motility, vitality and morphology in diluted-stored and post-thawed Hutsul semen, u...
Kähn W, Fraunholz J, Kaspar B, Pyczak T.Ultrasonography allows early and reliable pregnancy detection in several domestic animals. Transrectal sonography can be recommended in horses and cattle, transrectal or transcutaneous procedures in sheep, goats and pigs while transcutaneous ultrasound scanning is appropriate in dogs and cats. Three periods of time can be distinguished in the diagnosis of early pregnancy by ultrasound: the earliest phase, where signs of pregnancy can be found in some cases, but accuracy of diagnosis is very low; the succeeding period, where reliable diagnosis is possible, but results are often difficult to ach...
Jung C, Hospes R, Bostedt H, Litzke LF.To report on the outcome of surgical treatment of uterine torsion in preterm mares. Methods: Retrospective case series of pregnant mares with uterine torsion presented to the Clinic for Obstetrics, Gynaecology and Andrology of Large and Small Animals. Methods: Hospital records of all pregnant mares that underwent ventral midline laparotomy for uterine torsion between 1998 and 2004 were reviewed. The signalment, history, clinical signs, results of diagnostic procedures, direction and degree of the uterine twist, treatment and outcome were retrieved from each case record. Results: This study com...
Młodawska W, Palmer E, Duchamp G, Okólski A, Bézard J.The binding of a spermatozoon to the zona pellucida is the first step in fertilization. The number of spermatozoa bound to a zona pellucida may reflect the functional status of both the oocyte and spermatozoa. The aim of the present study was to determine whether the stage of maturation of the equine oocyte affects the capacity of the zona pellucida to bind with spermatozoa. Cumulus-oocyte complexes (COCs) were collected from the ovaries of mares from abattoirs or were obtained in vivo by ultrasound-guided follicular aspiration. Oocytes were inseminated directly after collection or after 30 h ...
