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Topic:Mares
Mares and horses are integral components of equine studies, focusing on the reproductive and behavioral aspects of equine biology. Mares, or adult female horses, play a significant role in breeding programs and are often studied for their reproductive physiology, gestation, and maternal behaviors. Horses, as a broader category, encompass both sexes and all age groups, providing a comprehensive view of equine anatomy, physiology, and behavior. Research in this area often investigates the differences and similarities between mares and other horses in terms of hormonal cycles, reproductive health, and social interactions. This page compiles peer-reviewed studies and scholarly articles that explore the biological and behavioral characteristics of mares and horses, offering insights into their roles in equine science and management.
Estrous cycle-dependent changes in platelet indices in healthy mares. Platelets (PLTs) are key regulators of hemostasis, inflammation, and tissue remodeling, and their phenotype is known to fluctuate with sex steroid concentrations in several species. However, the influence of the estrous cycle on PLT characteristics in mares has not been investigated. We hypothesized that PLT indices vary between reproductive phases in association with changes in estradiol-17β (E2) and progesterone (P4). The aim of this study was to characterize PLT indices in estrus and diestrus and to determine how these hematological parameters relate to circulating E2 and P4 concentrations...
Reduced centrifugation duration improves diagnostic performance of an equine tapeworm egg counting technique. Anoplocephala perfoliata, can cause severe health problems in horses. Standard coprological tests have performed poorly for detecting A. perfoliata, and while a centrifugation-enhanced flotation technique is superior to other techniques, it is time consuming due to three 10-minute centrifugation steps. This study aimed to evaluate modifications of this technique that reduce the centrifugation durations to 5 and 1 min, respectively. Fecal samples were collected from ten adult A. perfoliata egg count positive mares and divided into 9 subsamples to allow for three replicate counts for each of th...
Application of Anti-Müllerian Hormone in Regulation of Ovarian Function and Its Practical Relevance for Fertility and Embryo Production in Cows and Mares. In the female organism, Anti-Müllerian hormone (AMH) is produced exclusively by granulosa cells, particularly in secondary and early tertiary follicles. The amount of AMH released into the blood is proportional to the total number of follicles present in the ovaries and is therefore used to estimate the ovarian functional reserve. In both cattle and mares, a strong and highly repeatable association has also been demonstrated between AMH concentrations and antral follicle count. Therefore, AMH may serve as a biomarker with broad diagnostic utility in reproductive medicine in these species, as ...
Ovum pick-up in mares: Evidence review and best practice recommendations using a modified GRADE approach. Ovum pick-up (OPU) is a procedure that is now performed in mares worldwide to harvest oocytes for in vitro embryo production. There is a lack of consensus surrounding best practices for various procedural elements of the technique and recently there has been an increasing focus on the welfare aspects of the procedure. Our objective was to summarize current practice and to develop guidelines for OPU in the mare, using a modified GRADE approach to optimize efficiency and mare welfare. Published evidence on various aspects of the procedure was compiled, and to supplement the relative lack of publ...
Use of computer-assisted tomography for diagnosis and standing surgical reduction of progressive ethmoidal hematoma in a mare. Progressive ethmoidal hematoma (PEH) is a rare, nonneoplastic mass occurring in the sinonasal passages of horses. An 11-year-old, pregnant Thoroughbred mare was presented with a history of intermittent nasal discharge and stertorous respiration. On examination, radiography revealed increased opacity in the sinus and nasal cavities and endoscopy identified a mass emerging from the left ethmoidal turbinate. Computed tomography (CT) showed the range and origin of the mass, indicative of PEH. A standing frontonasal flap was made under sedation, following temporary tracheostomy to secure the airway...
Embryo developmental kinetics and vitrification in relation to pregnancy outcome, foaling percentage and foal sex. While fast in vitro embryo development has been associated with improved outcomes, the relationships of slow in vitro embryo development and vitrified versus fresh in vitro produced (IVP) embryo transfer to foaling percentage and foal sex are less explored. Objective: To determine the relationships of (1) day of blastocyst formation (D7-11 after intracytoplasmic sperm injection (ICSI)) and (2) vitrification and warming method (one- and three-step) versus fresh transfer with pregnancy, early pregnancy loss (EPL), foaling percentage and foal sex. Methods: Retrospective clinical study. Methods: B...
Comparative analysis of mesenchymal stromal cells derived from ovarian follicular aspirates of young and aged mares. Mesenchymal stromal cells from equine ovarian follicular aspirates represent a promising source for cell-based therapies. However, the age of the donor mare may alter their biological properties and therapeutic potential. This study aimed to evaluate the effect of age on MSCs from ovarian follicular aspirates of young (< 10 years, n = 5) and aged (≥ 18 years, n = 5) mares. MSCs were isolated, expanded, cryopreserved at passage 3, and subsequently thawed to evaluate proliferation, immunophenotype, differentiation capacity, and gene expression profiles. Proliferation rates, total cel...
Integrative and conjugative elements carrying high-level gentamicin resistance genes in Streptococcus dysgalactiae subsp. equisimilis from horses. In streptococci, the acquisition of high-level gentamicin resistance (HLGR) abolishes the synergy with beta-lactams, constituting a medical concern for humans and animals. This synergy between gentamicin and beta-lactams is useful to treat severe infections like endocarditis, among others. HLGR has been characterized mostly in roup B Streptococci mediated by the bi-functional gene (6)-(2).HLGR- subsp. () (=27) were isolated from the uterus of mares during a routine screening before fecundation. One HLGR- was isolated from a lymph node of a mare. The mares resided in six different studs locat...
Effect of N-acetyl cysteine treatment on uterine cytokine and chemokine profiles in mares with persistent breeding-induced endometritis. Persistent breeding-induced endometritis (PBIE) is a major cause of infertility in mares. Recent research has shown that PBIE-affected mares treated with intrauterine N-acetyl cysteine (NAC) 12 hours before breeding showed no improvement in clinical signs at 12- and 60-hours post-breeding. Objective: The present study was designed to examine the effects of NAC treatment on the uterine inflammatory cytokine and chemokine profiles in PBIE-affected mares. Methods: Using a randomized, blinded, cross-over design, mares susceptible to PBIE (n=9) were allocated to Control and Treatment cycles with at...
Retained fetal membranes in light breed mares hospitalized for attended parturition. Retention of fetal membranes (RFM) is well described in draft breeds, whereas data on light breed mares remains limited and inconsistent. Objective: This retrospective study aimed to describe the frequency, associated factors, treatments, and consequences of RFM in light breed mares hospitalized for attended parturition. Methods: Medical records of 321 light breed mares hospitalized for attended parturition at the Veterinary Teaching Hospital, University of Bologna, were retrospectively reviewed. Data collected included: breed, previous history of RFM, age, parity, assisted reproductive techni...
Visceral disseminated hemangiosarcoma causing severe bicytopenia in a mare. Hemangiosarcoma is an uncommon but highly aggressive malignant vascular neoplasm in horses, most often identified as a disseminated process at postmortem examination. This report describes an adult Warmblood mare presenting with acute hemorrhagic diarrhea, severe anemia, and thrombocytopenia associated with disseminated hemangiosarcoma likely originating in the transverse colon with metastasis to the liver and lungs. This case highlights gastrointestinal hemangiosarcoma as a potential differential diagnosis in horses with unexplained bicytopenia and hemorrhagic enteropathy.
Near-Term Extrauterine Pregnancy Secondary To Uterine Rupture In A Mare. Uterine rupture is an uncommon but life-threatening complication of equine reproduction, typically associated with dystocia, uterine torsion, fetal manipulation, or hydrops. Tears may occur in either the uterine horns or body, although involvement of the ventral uterine body is rare. This case report describes an 11-year-old Arabian mare at 350 days of gestation that developed abdominal pregnancy secondary to uterine torsion and full-thickness ventral uterine rupture, resulting in fetal death and the free presence of the fetus within the peritoneal cavity. Surgical removal of the fetus and pri...
Ovarian follicle dynamics in the plains zebra (Equus quagga). Understanding follicular dynamics during the estrous cycle is essential for developing breeding programs and assisted reproductive technologies (ARTs) in any species. In this context, knowledge of follicular dynamics and related uterine changes in the plains zebra (Equus quagga) is essential to increase the declining population of this vital African species and to provide comparative insights into more endangered zebra species. Likely due to the difficulty of handling these wild species, no detailed reproductive study using ultrasonography has been performed in any zebra. Therefore, the presen...
Verminous mastitis caused by Cephalobus cubaensis infection in a mare. A 7-y-old American Quarter Horse mare was presented to a veterinary hospital for ongoing reproductive monitoring and management of endometritis. During physical evaluation, several nodular lesions of unknown origin and duration were discovered in the mammae. Histologically, biopsies from the lesions were confirmed as severe granulomatous mastitis with intralesional rhabditid nematodes. A putative diagnosis of or infection was assigned, and ivermectin (1.2 mg/kg PO) treatment was given every 2 wk. When lesions persisted after the initial dose of ivermectin, PCR testing of and gene targe...
Insights from healthy mares reveal that mammalian uteri harbor a diverse virome. The Earth's estimated 10 virions, primarily phages, significantly impact microbial ecosystems. Despite their abundance, viromes remain relatively understudied-particularly in domestic animals. While recent studies have described a dynamic commensal microbiome in mammalian uteri, no research has yet characterized the commensal virome in a mammalian uterus. In this study, we report for the first time the presence of a sparse, but diverse native virome in the equine uterus. The resulting virome database consists of 513 non-redundant viral genomes (> 2 kb). Taxonomic annotations revealed the...
Detection of papillomavirus DNA in uterine flushing samples from healthy mares reveals diverse genotypes with differing host ranges. A molecular study to assess the presence of some papillomaviruses was performed on 105 uterine flushing samples of healthy mares using real time quantitative polymerase chain reaction (qPCR) and digital PCR (dPCR). Bovine, equine, and ovine papillomavirus DNA was detected in 27 uterine flushing samples through dPCR (~ 25.71%); qPCR was able to detect 18 positive samples (~ 17.14%). Differences between the two molecular protocols were significant as shown by McNemar's test (p˂ 0.005). EcPV DNA was detected in 10 samples by dPCR (~ 9.52%) of uterine flushing samples. qPCR detected EcPV DN...
Molecular detection of pathogenic Leptospira spp. in mares with reproductive disorders enrolled in embryo transfer programs. Equine genital leptospirosis (EGL) is associated with reproductive disorders in mares. However, its occurrence in embryo transfer (ET) programs remains poorly characterized. Objective: Given the scarcity of data on the circulation of Leptospira spp. in mares enrolled in ET programs, this study aimed to investigate the serological and molecular occurrence of Leptospira spp. in mares with a history of reproductive disorders from 13 stud farms dedicated to embryo transfer in Brazil. Methods: Serum and endometrial cytobrush samples (ECS) were collected from 70 unvaccinated mares. Serological analy...
The effects of citrulline on horse milk components and fecal metabolism were analyzed based on LC-MS and 16s amplicon. The lactation period in mares is critical, as it significantly influences foal health and subsequent reproductive outcomes. Developing a precise nutritional strategy for lactating mares is a primary research focus. L-citrulline, a bioactivenon-protein amino acid and precursor to arginine, has been shown to enhance mammary blood flow and reduce oxidative stress, yielding promising results in livestock lactation studies. However, research on its effects in Equus species remains limited. There is a notable gap in data regarding its impact on lactation performance blood biochemistry, and its role ...
FGF2, LIF, and IGF1 supplementation during in vitro maturation or culture improves equine ICSI embryo development in an age-dependent manner. Ovum pickup (OPU) combined with intracytoplasmic sperm injection (ICSI) has reshaped equine assisted reproduction, enabling embryo production from mares and stallions with constrained breeding opportunities; however, limited efficiency of in vitro maturation (IVM) and in vitro culture (IVC) continues to hinder embryo production. Growth factor supplementation with fibroblast growth factor 2 (FGF2), leukemia inhibitory factor (LIF), and insulin-like growth factor 1 (IGF1) in combination (FLI) has been shown to enhance oocyte and embryo developmental competence in several species. Objective: This...
Factors influencing gestation length in Mares in the Tiaret region, Algeria. Gestation length is a key parameter in equine reproductive management, yet its variability remains poorly documented in Barb and Arabian mares under Algerian conditions. Objective: This study aims to determine gestation length in mares and to assess the influence of various factors, including breed, year of mating, mating month, mare age, parity, reproductive status, stallion and the foal's sex on gestation duration. Methods: A total of 133 mares from the National Stud Farm of Tiaret (Algeria) were monitored over the period 2021-2024. Results: The mean gestation length was 332.5 days (range: 3...
The Equine Reproductive Microbiota: Composition, Dynamics, Dysbiosis, and Implications for Fertility in Mares and Stallions. The equine reproductive microbiota has emerged as an important factor influencing reproductive health and fertility in both mares and stallions. Traditionally, the equine uterus was considered sterile, and microbial presence was interpreted primarily in the context of infection. However, sequencing-based studies have demonstrated that the reproductive tract, including the uterus and semen, contains detectable microbial communities or microbial DNA signatures, challenging this traditional paradigm. In mares, the vaginal microbiota is consistently dominated by , , , and , whereas the uterine env...
The Effects of L-Citrulline on the Apparent Digestion and Metabolism of Nutrients, Blood Hormone Levels, Amino Acid Metabolism and the Diversity of Faecal Microbiota in Mares in the Later Stage of Pregnancy. This study aimed to investigate the impact of dietary L-citrulline supplementation on the health of mares during late gestation. Thirty-two healthy mares in late pregnancy were randomly assigned to four groups: a control group (CON, 0 g/d) and three treatment groups receiving 15, 30, and 45 g/d/head of L-citrulline, respectively. The trial spanned 72 days, including a 12-day adaptation phase and a 60-day formal feeding period. A fixed daily feeding amount of 11.2 kg/head was provided, ensuring complete consumption and consistent dry matter intake across all groups. Results demonstrated that su...
Prepubic Tendon Rupture and Uterine Herniation in a Late-Term Kurdish Mare: A Case Report. Prepubic tendon rupture (PPTR) is a rare but life-threatening complication in late-term pregnant mares. It results in abdominal wall failure, ventral oedema and a poor prognosis for both the mare and foetus. A 14-year-old multiparous Kurdish mare at approximately 310 days of gestation presented with acute ventral distension, reluctance to walk and cranial displacement of the udder. Clinical evaluation revealed tachycardia, pallor and Grade 3/4 ventral oedema. Haematology indicated leucocytosis and haemoconcentration. Transabdominal ultrasonography showed a viable foetus and severe thinning of ...
Hyperactivation and Tyrosine Phosphorylation of Cryopreserved Stallion Spermatozoa in Relation to Conventional In Vitro Fertilization Blastocyst Production. Challenges in establishing clinical conventional in vitro fertilization (IVF) in horses include variation in sperm and oocyte quality, which can be affected by mare age. Extended preincubation of stallion spermatozoa has resulted in successful IVF. However, there is limited research on the impact of preincubation on sperm characteristics and IVF success. Objective: Responses of frozen-thawed stallion spermatozoa over time under IVF preincubation conditions were evaluated, and samples based on specific responses were tested for their ability to fertilize oocytes, including those from older mare...
Age, embryo donor status, and insemination with chilled semen all predispose to persistent breeding-induced endometritis in warmblood mares. Persistent breeding-induced endometritis (PBIE) is a common reason for mares failing to establish pregnancy. Objective: To examine the hypothesis that advancing mare age and embryo donor status predispose to PBIE and compromise fertility. Methods: Retrospective analysis of the impact of mare age, breeding system (embryo donor versus broodmare), and semen type (chilled versus frozen-thawed) on the likelihood of PBIE and subsequent pregnancy/embryo recovery. Methods: Warmblood mares (n = 769) inseminated during 1745 oestrous cycles were divided into three age categories (≤6, 7-13 and ≥14...
Epidemiology of open and closed diastemata in equine cheek teeth and associations with periodontal pathology. Cheek-tooth diastemata are a common dental abnormality in horses and are considered a major predisposing factor for periodontal disease. However, the influence of diastema type and anatomical location on disease severity remains incompletely understood. To determine the prevalence and distribution of open and closed cheek-tooth diastemata and evaluate their association with periodontal disease severity in horses, while assessing the influence of age, sex, jaw location and laterality, fifty equine cadaver heads obtained from an abattoir were examined. Diastemata were identified through visual a...
Milk productivity of mares. To determine the milk productivity of Kazakh horses of the Adai region in variants of selection and technological indicators of milk for the production of cumus in the conditions of the Mangyshlak peninsula of the Republic of Kazakhstan. The object of the study was the Kazakh horse of the Adai intra-breed type at "Taushyk" LLP (Tupkaragan District, Mangystau Region). Mares with a more pronounced milk production were selected and analyzed . they have investigated the quality of milk for further processing. A characteristic feature of the dynamics of milk sugar content during lactation has been ...
Relationship between the estrus duration in cyclic mares and the endometrial gene expression on day 7 post-ovulation. This study investigated the effect of estrus duration on endometrial gene expression in cyclic mares on Day 7 post-ovulation, focusing on transcripts relevant to early pregnancy: uterocalin (P19), insulin-like growth factor 1 (IGF1), fibroblast growth factor 2 (FGF2), progesterone receptor (PGR), and estrogen receptor alpha (ESR1). Twelve mares were classified according to the estrus duration in long estrus (LE, ≥ 3 days of endometrial edema; n = 7) or short estrus (SE, 0.1). ESR1 expression was undetectable in all samples. These findings suggest that prolonged estrus enhances P19 e...
Physiological and nutritional adaptation of broodmares during the transition from late pregnancy to early lactation: Digestibility changes and the role of uNDF as an internal marker. Nutritional management of broodmares during late pregnancy and early lactation is essential for maternal health and foal well-being. This study evaluated a targeted dietary adaptation during the transition from late gestation to early lactation, monitored nutrient digestibility, and applied undigested neutral detergent fiber (uNDF) as an intrinsic digestibility marker. A prospective nutritional study was conducted on 11 clinically healthy Trotter broodmares (3 primiparous, 8 multiparous) monitored under standardized conditions. Mares received a forage-based diet with controlled starch intake a...
Comparative analysis of the transcriptome and methylome in distinct trophoblast populations at the time of embryo implantation in mares. BACKGROUND: During equine implantation, two distinct trophoblast subpopulations are identified: the invasive chorionic girdle (CG) and the non-invasive allantochorion. The invasive CG trophoblast is believed to modulate the maternal immune response and facilitates embryo attachment to the endometrium, while the allantochorion contributes to placental development without breaching the endometrium. However, the mechanisms underlying differential adhesion and immune modulation by these two lineages remain poorly understood. This study aimed to investigate the regulation of biological processes un...
