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.
HOLMES AD, JONES CP.Fifteen samples of mares' milk with initial potencies of from 86 mg to 161 mg of reduced ascorbic acid per liter were stored in the dark at 10°C. They were assayed at daily or longer intervals. Four samples observed for 10 days lost an average of 2.5 mg per liter daily; 4 samples stored 20 days lost 1.8 mg per day; 2 stored 28 days lost 1.3 mg daily; and 3 observed for 33 days lost 1.1 mg per liter per day. These data show that the rate of loss of reduced ascorbic acid from mares' milk is only a fraction of the rate of loss from cows' milk.
Loy J, Sornalingam K, Cawley A, Scrivener C, Keledjian J, Noble GK.Altrenogest is a synthetic progestogen widely used in equine reproductive management. Adverse effects to altrenogest have been reported in people with cutaneous exposure reported as the highest exposure pathway. Despite these reports, there has been no quantitative research to determine the capacity for altrenogest to be absorbed through skin. This study aimed to determine if cutaneous application of oral altrenogest results in systemic absorption in mares and to evaluate the influence of application site. A randomized, two-period, two-treatment crossover study was undertaken in eight mares. M...
Çortu A, Çınar H.Rectal examination is routine in equine reproduction but may trigger acute stress affecting welfare and safety. Intraocular pressure (IOP) responds rapidly to autonomic changes and may capture short-lived stress responses. Objective: To evaluate whether rectal examination acutely affects IOP and behavioral responses in mares, and whether reactions differ by reproductive status. Methods: Twenty Rahvan mares (10 pregnant, 30-40 days' gestation; 10 non-pregnant; 4-7 years) underwent transrectal examination without sedation. IOP was measured bilaterally at six time points: 2 min pre-exam (T1), dur...
Donato GG, Necchi D, Gionechetti F, Ala U, Nebbia P, Robino P, Stella MC, Vandaele H, Pallavicini A, Nervo T.In the past, bacteria detected in the mare's uterus were generally interpreted as a sign of endometritis, since the uterus was considered a sterile environment. This assumption has been challenged by the introduction of culture-independent molecular techniques, particularly 16S rRNA amplicon sequencing, which have demonstrated that healthy mares harbor an endometrial microbiota. The aim of this study was to characterize the endometrial microbiota of healthy mares and to determine whether microbial composition differs between estrus and diestrus. Endometrial samples were collected from eleven h...
Li X, Qian S, Yang L, Yang X, Chang X, Zeng Y, Meng J.This study aimed to investigate the relationship between genes and metabolites involved in glycogen metabolism across different tissues of Yili mares using joint transcriptomic and metabolomic analyses. Glycogen content was measured in various tissues (pincer, trapezius, latissimus dorsi, gluteus medius, semitendinosus, external abdominal obliques, liver, and heart) from seven Yili mares. The liver, as the visceral tissue with the highest glycogen content, and the gluteus medius, as the muscle with the highest glycogen content, were selected for transcriptomic sequencing and metabolomic analys...
González N, Varela A, de Blas N, Gil L.At present, oviductal pathologies and their influence on mare fertility have not been clearly determined. Checking changes throughout the year in the oviductal structure may be relevant to understand the influence on the appearance of problems in oviductal functionality and, thus, the impact on fertility, which is the objective of this work. The oviducts of 56 mares were examined. Their anatomy, permeability, oviductal cellularity and the presence of pathologies were assessed to establish the correlations between the time of the year and each of these parameters. We cannot conclude whether the...
Magdesian KG.Alloimmune disorders occur in foals when pregnant mares produce antibodies against antigens on the foal's cells or tissues, and concentrate them within colostrum. Once foals nurse and absorb colostral antibodies, they can develop hematologic or cutaneous manifestations that can occur individually or in combination. These include neonatal isoerythrolysis, a hemolytic anemia directed against factors on the foal's erythrocytes, alloimmune thrombocytopenia when the antibodies are directed against platelet antigens, alloimmune neutropenia when they are directed against neutrophil antigens, and a co...
Derbala MK, Sargious MAN, Hagag NM, Pycock JF, Abu-Seida AM.Twin pregnancy in mares is one of the leading causes of abortions. Abortion invariably impacts both fetuses. This report describes an unusual case of a twin surviving to term following the abortion of its co-twin at 9 months in a 7-year-old Egyptian Arabian mare. At the time of abortion at 9 months of gestation, the size of the aborted fetus was equivalent to one of approximately 5 months of age while the age of the live co-twin was 9 months. Both fetuses were males. A skin sample was collected from the aborted fetus and hair samples were collected from the dam, sire and live foal for parentag...
Steiner MN, Boone LH, Hayden L, Schumacher J, Arnold CE.To describe the indications for and surgical technique of mastectomy of mares and to describe the outcome of 10 mares that underwent mastectomy in a retrospective case series. Methods: 10 mares having disease of one or both mammary glands. Methods: Medical records (1995 to 2022) from 2 university teaching hospitals were searched to identify mares that had undergone unilateral or bilateral mastectomy. Data regarding history, signalment, diagnostic tests, preoperative treatment, surgical procedure, and postoperative management were reviewed. Follow-up information was obtained by interviewing the...
Gallacher K, Woolford L, Santos LC, Serpa PBS, Len J, Gilbert RO, Kind KL.Endometrial health is vital for the reproductive efficiency of broodmares and accurate diagnostic testing is crucial for directing the best treatment options and outcomes. Confocal laser endomicroscopy (CLE) is an endoscopic technique for obtaining in-vivo, real-time microscopic imaging of tissues using a fiber optic probe. CLE relies on induced tissue fluorescence and fluorescein sodium, given intravenously, is the contrast agent most used in human medicine. This study aimed to determine the feasibility of CLE for imaging equine endometrium and determine a standard dose of fluorescein sodium ...
Pasch L, Stefanovski D, Dobbie T, Lewis G, Turner RM.Historically, 8 × 0.5 ml straws, containing approximately 800 million sperm and 250 million progressively motile sperm were provided as a single 'breeding dose' of cryopreserved stallion semen. With the use of deep horn artificial insemination, there is a trend to reduce the number of 0.5 ml straws sold as a breeding dose, sometimes down to as little as one straw. Our aims were to determine if the number of straws provided as a breeding dose, as well as other mare, stallion and management factors, have an impact on pregnancy outcome in mares inseminated with cryopreserved semen. Unexpectedly,...
Kelley D, Walbornn S, Bartley C, Kaczor J, Premanandan C, Newton N, Holland R, Schnobrich M.Amnion-derived acellular bioscaffold (ADABP) products demonstrate interesting anti-inflammatory and healing properties which could be beneficial for intrauterine use. The objective of this study was to evaluate the safety of intrauterine injection of ADABP on systemic and uterine health. The study design randomly assigned subjects to one of two groups, control mares (n = 3) which received 3 mL injection of sterile saline in the base of each uterine horn, and treatment mares (n = 9) which received 3 mL of ADABP in the base of one uterine horn and 3 mL injection of sterile saline in the base of ...
Affonso FJ, Alonso MA, Bringel B, Douglas R, de Paula Nogueira G, Boakari YL, Fernandes CB.Glucose metabolism adapts to gestation, resulting in progressive physiological insulin resistance and increased insulin secretion to maintain maternal euglycemia and glucose availability for the developing fetus. These changes can impact mare fertility and maternal and neonatal health. This is the first comparison of body condition, regional adiposity, insulin and glucose dynamics, lipid metabolism, and cytokine production between lactating and non-lactating mares before, during pregnancy, and early postpartum. Twelve pregnancies from 9 broodmares, five nonlactating (NL) and seven lactating (L...
Gaber JTH, Cuervo-Arango J, Plaza-Dávila M, Martínez-Boví R.This experiment was performed to evaluate whether intrafollicular treatment of PGE2 or PGF2α administered in early estrus would induce normal ovulation, progesterone production (Experiment 1) and pregnancy (Experiment 2). In Experiment 1, mares in estrus after 2 days of endometrial edema were injected in all largest dominant follicles (28-35 mm in diameter) with 0.5 mL of sterile water containing 500 μg PGE2 (n = 6), 125 μg PGF2α (n = 6) or placebo (n = 7) (Hour 0). Ultrasound examinations were performed daily, until ovulation or anovulation was detected, and daily blood samples ...
Blanco-Doval A, Barron LJR, Bustamante MÁ, Aldai N.Mare milk has often been considered a food product with potential functional properties. However, the bioactive compound composition of mare milk, including vitamins and other minor bioactive compounds, as well as factors affecting this composition have scarcely been studied. Therefore, the present study aimed to characterize the changes during lactation in the content of water- and fat-soluble vitamins and total polyphenols, and the total antioxidant capacity of mare milk from semi-extensive farms. A total of 310 individual milk samples from 18 mares belonging to three commercial farms and 12...
Teixeira-Soares CM, Viana AG, Carvalho RPR, Barros E, Ramirez-Lopez C, Moura AA, Machado-Neves M.Endometritis is the leading cause of subfertility in mares and a significant challenge to equine reproduction. Unraveling uterine fluid proteome may promote advancements in the knowledge of endometritis etiopathogeneses and its diagnosis and therapeutic practices. Therefore, we aimed to characterize and compare the protein profile of the uterine fluid from healthy mares and animals diagnosed with endometritis. Mangalarga Marchador breed mares from Muriaé - Brazil were divided into control, infectious endometritis, and post-breeding endometritis groups (n = 8/ group). Uterine fluid was collect...
Cuervo-Arango J.The objective of this study was to compare the fertility of diestrous mares with a follicle ≥ 30 mm in diameter treated with prostaglandin F2α (PGF) (PGF group) or left untreated for 7 days (SP group). Standardbred mares (n = 46) were assigned randomly to the SP (n = 23) and PGF groups (n = 23) when they were identified with a corpus luteum (CL) of unknown age and a follicle ≥ 30 mm in diameter (Day 0). The most frequent outcome in the PGF group was estrus and ovulation of the dominant follicle (74 %), while the outcomes of the SP mares 7 days after Day 0 were more variable: estrus and fo...
Stoneham SJ, Tyler N, Holmes MA, Archer DC.This prospective, controlled field trial aimed to determine the effect of dietary supplementation of mares in late pregnancy with a commercial stud feed balancer on the transfer of passive immunity to their foals. Eighty-two pregnant mares on a single stud farm that were eligible for inclusion were assigned into two groups (Intervention and Control) based primarily on existing social groupings. Between 64-224 days prepartum, all mares received the same forage-based diet but mares in the Intervention group received an in-feed commercial stud feed balancer and mares in the Control group received...
Angyal E, Vincze B, Somoskői B, Sós-Koroknai V, Balogh P, Dankó GN, Cseh S, Kútvölgyi G.The anti-Müllerian hormone (AMH) is a granulosa cell-derived hormone that has been associated with female fertility and reflects the population of growing follicles. This study aimed to evaluate the average concentration of AMH in Lipizzaner mares, as well as to determine the relationship between AMH concentration and follicle number and size. We also investigated the relationship between the age of mares and their AMH levels. The possible effect of seasonality of AMH levels was also assessed. Twenty-three mares between 6 and 24 years of age were included in the experiment. Mares were divided...
Salcedo-Jiménez R, Kenney DG, Dubois MS.This case series reports four late pregnancy broodmares that were diagnosed with bladder rupture. The initial presentations were abdominal discomfort (n = 3) and dystocia (n = 1). All mares (n = 4) were overdue or at their expected time of delivery. Three mares showed clinical signs related to bladder rupture: pollakiuria (n = 2) and hematuria (n = 1). At the time of diagnosis, three mares had increased peritoneal fluid creatinine, the mean peritoneal: serum creatinine ratio was 4.1, and the bladder tear was observed via cystoscopy in 3 cases. Two mares were discharged from the hospital. Compl...
Fischetti L, Perina F, Sarli G, Ellero N, Freccero F, Castagnetti C, Mariella J.A 286-day pregnant mare was referred for signs of impending abortion. The ultrasonographic evaluation revealed a high normal combined thickness of the utero-placental unit (CTUP), oligohydroallantois and a living fetus. No vulvar discharge was observed, and the cervical swab culture was negative. After a choke, the mare received NSAIDs and antibiotics and then developed systemic inflammatory response syndrome (SIRS) and aborted. The amniotic portion of the umbilical cord was excessively long and twisted and the chorionic side of the placenta showed a brown discoloration and rough surface area....
Bailey CS, Beachler TM, Mochel JP, Wulf LW, Yaeger M, Kundu D, Withowski K, Papich MG.Despite their widespread clinical use, there is limited pharmacokinetic data for many equine intrauterine antimicrobials. This study aimed to measure the concentration of gentamicin and penicillin in the uterine fluid of mares following infusion of either a standard (PPGent) or long-acting (LA-PPGent) compounded formulation. We hypothesized that both formulations would result in therapeutic concentrations, with total concentrations sustained for longer using the long-acting formulation. Mares were administered 2400 mg of procaine penicillin and 200 mg of gentamicin via a single intrauterin...
Lection J, Schnobrich M, Wagner B, Byron M, Back B, Rollins A, Castro Alves RF, Cheong SH, Diel de Amorim M.To evaluate inflammatory cytokine and chemokine concentrations in endometrial samples collected by cytobrush or swab as a potential screening diagnostic marker for equine endometritis. Unassigned: 88 mares had endometrial samples collected, which included cytobrush, swab, and/or biopsy. Clinical reproductive records, reproductive ultrasound examination, endometrial cytology and culture results, and biopsy grading score were recorded. Fluorescent bead-based multiplex assays for the inflammatory markers interferon-γ, interferon-α, IL-1β, IL-4, IL-10, IL-17A, soluble CD14, tumor necrosis facto...
Neto ME, Curcio BR, Rafael LA, Pivato GM, Silva GC, Souza RP, Mousquer MA, Nogueira CEW.The cesarian section (C-section) is a potential risk factor for retained fetal membranes (RFM) in mares, requiring prompt diagnosis and treatment to enhance outcomes. This study aimed to evaluate the use of umbilical vessel infusion for the treatment of RFM after elective C-section in mares. Ten pregnant criollo type-mares at 315 days of gestation were monitored daily and underwent elective C-section upon readiness for birth. All mares exhibited RFM, with placentas retained beyond three hours careful extraction of the foal by C-section. Those were randomly assigned into two groups: Umbilical v...
Merari A, Fielding L.To describe patient characteristics, laboratory data, fetal orientation, methods of correction, survival, and treatment in miniature equids with dystocia. Methods: Retrospective study conducted from January 2002 to June 2023. Methods: Equine referral hospital and field service. Methods: Seventy animals with a total of 78 instances of dystocia. Methods: None. Results: Recorded variables included signalment, clinicopathologic data, fetal presentation, correction method, survival to discharge, and complications. The survival of miniature equid mares was 94% (73/78), while survival of foals was 17...
Atayde MF, Vidondo B, Bruckmaier R, Freymond SB, Sieme H, Rey-Kaeser R, Burger D.In-hand breeding involving restraint methods is likely the most common practice in the horse breeding industry worldwide. However, welfare issues that arise from such management have not been investigated in detail. Objective: (1) To investigate whether the mares show increased stress responses during in-hand breeding using (a) a lip twitch and (b) hobbles. (2) To evaluate if the use of restraint methods influences the mare's expression of oestrous behaviour. Methods: Intra-individual cross-over design. Methods: Six Franches-Montagnes stallions and 10 warmblood mares were used in these experim...
Hedia M, Leroy JLMR, Loomans S, Benedetti C, Angel-Velez D, Chiers K, Govaere J, Van Soom A, Smits K.Lipopolysaccharide (LPS) in follicular fluid impairs steroid production and oocyte developmental competence in cows and mice. This study assessed LPS concentrations in equine follicular fluid and their association with steroid and some cytokine levels. Additionally, we evaluated whether LPS exposure during in vitro maturation (IVM) affects equine oocyte developmental competence. In experiment 1, follicular fluid from large follicles (>30 mm in diameter) was collected from 16 slaughterhouse mares, and concentrations of LPS, estradiol, progesterone, TNF-α, and IL-6 were measured. In experiment...
Carey KJ, Smith I, Hartley CA, Bailey KE, McIntosh K, Broder CC, Gilkerson JR.Hendra virus (HeV) is a high consequence pathogen that causes severe respiratory and/or neurological disease in both horses and humans with high mortality. The equine vaccine, Equivac® HeV, is a recombinant soluble version of the G glycoprotein of HeV (HeV-sG) that elicits a potent HeV-neutralising antibody response in adult horses and also provides indirect protection for humans. Maternally derived HeV-G specific antibodies could interfere with subsequent foal vaccination, although other factors such as foal age and the suitability of vaccination protocols that have been optimised for adult ...
Sharshar A, Hammad A, Salem M, El-Sunsafty M.This study was carried out to evaluate a rectal pull-back one-stage technique, which is a modification of the one-stage Goetz technique, for treating third-degree perineal laceration or rectovestibular fistula. Methods: This study was performed on 12 mares, ten of whom suffered from third-grade perineal laceration, and two suffered from rectovestibular fistula and were included in this study. After incision of the vestibular shelf horizontally, the dissected rectal flap was pulled caudally and sutured to the anal sphincter during its reconstruction at the final stage. While the vestibular shel...
Motta D, Pedrosa J, Lilenbaum W.Leptospirosis is a zoonotic disease caused by pathogenic bacteria of the genus Leptospira. A lesser-known form, equine genital leptospirosis (EGL), has been identified as a chronic and often silent infection involving the colonisation of the mare's genital tract. Despite its potential impact, EGL remains underdiagnosed and poorly understood, particularly in its association with reproductive inefficiency. This study showed the presence of Leptospira spp. DNA by lipL32-PCR in the genital tract of mares with a history of reproductive disturbances. Cervicovaginal mucus samples were collected from ...
