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.
The Journal of heredityJanuary 1, 1964
Volume 55 31-38 doi: 10.1093/oxfordjournals.jhered.a107283
BENIRSCHKE K, LOW RJ, SULLIVAN MM, CARTER RM.This study is oriented towards explaining the usual infertility observed in mule and hinny species through a detailed investigation of their chromosomal structures, with a special emphasis on the instances […]
Moustafa A, Elmetwally M, El-Khodery S, Hamed M, Gomaa N, Rizk MA.There is a paucity of information regarding the frequency and risk factors associated with the occurrence of an abdominal hernia in different equine species especially donkeys, and mules. In addition, the effectiveness of using polypropylene mesh for the surgical management of abdominal hernia in donkeys and mules is still unknown. The purpose of the present study was to evaluate the efficacy of using polypropylene mesh for the surgical treatment of abdominal hernia in horses, donkeys, and mules and to address the occurrence and risk factors associated with an abdominal hernia in the selected ...
Joonè CJ, Cavalieri J.There is a need for a safe, effective and practical method of oestrus suppression in the mare. The aim of this study was to monitor ovarian activity in mares exposed to either 9.4 or 28.2 mg deslorelin acetate, a GnRH agonist, in the form of a sustained-release implant. Following oestrus synchronisation, mares were randomly assigned to one of three groups (n = 4 per group) and administered either one (Des1 group; 9.4 mg) or three (Des3 group; 28.2 mg) implants of deslorelin acetate (Suprelorin-12, Virbac Australia) or one blank implant (Control group; Virbac Australia). Mares underwe...
Ginther OJ, Bergfelt DR.Seasonally anovulatory mares were injected, i.m., twice daily with a GnRH analogue (GnRH-A), and hCG was given when the largest follicle reached 35 mm in diameter. In Exp. 1, treatment was initiated on 23 December when the largest follicle per mare was less than or equal to 17 mm. An ovulatory response (ovulation within 21 days) occurred in 17 of 30 (57%) GnRH-A-treated mares on a mean of 15.8 days. The shortest interval to ovulation in control mares (N = 10) was 57 days. The diameter of the largest follicle first increased significantly 6 days after start of treatment. In Exp. 2, treatment wa...
Steuer AE, Anderson HP, Shepherd T, Clark M, Scare JA, Gravatte HS, Nielsen MK.Horses are host to a plethora of parasites. Knowledge of the seasonality of parasite egg shedding and transmission is important for constructing parasite control programs. However, studies describing these patterns are sparse, and have largely been conducted only in the United Kingdom. This study evaluated strongylid egg shedding patterns and transmission dynamics of Strongylus vulgaris in naturally infected and untreated mares and foals through one calendar year in Kentucky, USA. The study also investigated the existence of a peri-parturient rise (PPR) in strongylid egg counts in foaling mare...
Nardi S, Nuti M, Nocera I, Sgorbini M, Marmorini P, Barsotti G.This study assesses lacrimal secretion in healthy foals within 48 hours after birth and evaluates their variations in lacrimal secretion and menace response appearance during the first month of life. A total of 31 Standardbred foals were evaluated. Foals were housed with their dams in 4 × 4 m boxes throughout the study. A complete ophthalmic examination was performed for each animal enrolled in the study, including the foals' dams which were used as a control group to compare the lacrimal secretion of foals at birth with that of adult horses. In foals, the Schirmer Tear Test I (STT I) and m...
Gáspárdy A, Gallagher G, Bartha B, Cseh S, Fekete SG, Somoskői B.The authors aimed to determine the plasma melatonin concentration in mares and their new-born foals in the early post-partum period. Blood samples were collected from the jugular vein of 53 mare-foal pairs within twelve hours after parturition. Plasma melatonin levels were measured by ELISA. The melatonin concentration, adjusted for the moment of parturition using a generalised linear model, was 34.58 pg mL-1 in mares. It was significantly lower (27.63 pg mL-1) in the new-born foals. However, the melatonin concentration declined differently by the end of the twelve hours, it decreased less in...
Dell'aquila ME, Fusco S, Lacalandra GM, Maritato F.The aim of this study was to develope an efficient and reproducible procedure for in vitro maturation (IVM) and fertilization (IVF) in the horse. Cumulus-oocyte complexes (COCs) recovered from the ovaries of mares slaughtered during the breeding season were morphologically evaluated, and those showing a compact cumulus and homogeneously appearing cytoplasm were selected for culture. Effects on the maturation of estrous mare serum (EMS) versus estrous cow serum (ECS) as medium supplement were also evaluated (Experiment 1). In Experiment 2, the fertilization of in vitro matured oocytes with froz...
Hohenhaus MU, Bostedt H.108 mares with a total of 135 oestrous cycles were examined. 30% of the mares showed development of double follicles, found by palpation and ultrasonography. Eight cases of double ovulation, four of them synchronous and four asynchronous, were examined closely. These cases of double ovulation showed different growth and different development of the follicular wall. This occurred at the same time in cases of synchronous double ovulation whereas it differed in case of asynchronous double ovulation. The later ovulating follicle was still growing while the first one had already burst. With both fo...
Kohn CW, Knight D, Hueston W, Jacobs R, Reed SM.Immunoglobulin G, IgM, and IgA concentrations were measured in serum collected from 36 Standardbred mares within 12 hours of foaling, in colostrum collected within 6 hours of foaling, and in serum collected from foals 24 to 48 hours after birth. In serum collected from mares after parturition, mean concentrations of IgG, IgM, and IgA were 2,463.9 +/- 1,337.3 mg/dl, 136.4 +/- 218 mg/dl, and 305.2 +/- 237.5 mg/dl, respectively. In serum from foals, mean concentrations of IgG, IgM, and IgA were 1,953.3 +/- 1,635 mg/dl, 33.8 +/- 30.4 mg/dl, and 58.4 +/- 42.2 mg/dl, respectively. In colostrum, mean...
Krohn J, Ennen S, Hospes R et al. Use of a cervical stent for long-term treatment of pyometra in the mare: A report of three cases. Reprod Dom Anim 2019; 55: 1155–1159 DIE PYOMETRA DER STUTE IST EIN CHRONISCHER ENTZüNDUNGSZUSTAND DES ENDOMETRIUMS, DER HäUFIG MIT DER AKKUMULATION GROßER MENGEN AN SEKRET EINHERGEHT. PRäDISPONIERT SIND STUTEN MIT VERäNDERUNGEN DER ZERVIX, DURCH DIE DIE UTERINE CLEARANCE BEEINTRäCHTIGT WIRD. DIE HäUFIG UNSPEZIFISCHEN SYMPTOME UMFASSEN LEISTUNGSMANGEL, KONDITIONSVERLUST, SUBFEBRILE TEMPERATUR ODER KOLIKARTIGE SCHMERZEN. MANCHE TIERE PRäSENTIEREN SICH SYMP...
Brück I, Bézard J, Baltsen M, Synnestvedt B, Couty I, Greve T, Duchamp G.In mares, the shortage of oocytes and the variability in nuclear maturation at a certain time of the oestrous cycle hinders the optimization of methods for in vitro maturation and in vitro fertilization. Increasing the number of small-to-medium-sized follicles available for aspiration in vivo may increase the overall oocyte yield. The aims of the present study were to investigate whether administration of crude equine gonadotrophins affects follicular development, oocyte recovery rate, in vivo oocyte maturation and follicular concentrations of meiosis-activating sterols. During oestrus, all fo...
Thorson JF, Karren BJ, Bauer ML, Cavinder CA, Coverdale JA, Hammer CJ.To investigate the maternal plane of nutrition and role of Se yeast on foaling variables and passive transfer of IgG, 28 Quarter Horse mares were used in a study with a randomized complete block design. Mares were blocked by expected foaling date and assigned randomly within block to dietary treatments. Dietary treatments were arranged as a 2 x 2 factorial with 2 planes of nutrition, pasture or pasture + grain mix (fed at 0.75% of BW on an as-fed basis) and 2 concentrations of Se yeast (0 or 0.3 mg/kg of DMI). This resulted in 4 treatments: pasture (PA), pasture + Se (PS), pasture + grain mix ...
Ball BA, Little TV, Weber JA, Woods GL.The estimated embryonic loss rate between Days 4 and 14 after ovulation for young, normal mares (9%) was significantly lower (P less than 0.01) than the estimated embryonic loss rate for aged subfertile mares (62%). Fertilization rates, which were based on the recovery of embryos at Day 4 after ovulation, were 96% and 81% (P less than 0.1) for normal and subfertile mares, respectively. Day-4 embryos were collected from the oviducts of normal and subfertile donors mares. These embryos were transferred to the uteri of synchronized, normal recipient mares to test the hypothesis that the high inci...
Rigby S, Love C, Carpenter K, Varner D, Blanchard T.Eleven light-breed pregnant mares (335 to 347 d gestaton) were used to evaluate the use of prostaglandin E2 as a cervical ripening agent prior to induction of parturition during the months of April and May. Six hours prior to induction, each mare's cervix was examined per vagina for softness and dilation. Each mare was then assigned to 1 of 2 treatment groups: Group PGE mares (n = 7) received 2.0 to 2.5 mg prostaglandin E2 deposited intracervically; Group SAL mares (n = 4) received 0.5 mL of sterile NaCl deposited intracervically. Six hours later, the mares were readied for parturition by wrap...
Fodor L, Szenci O, Peters M, Varga J, Szemerédi G, Wyszoczky F.A total of seven Bacteroides ureolyticus strains were isolated from the cervix and the clitoral fossa of mares with vaginal discharge. No other bacteria capable of causing metritis or vaginitis were isolated from the samples. The isolated strains resembled Taylorella equigenitalis. Both species are catalase, oxidase and alkaline phosphatase positive, but, in addition to these characteristics, B. ureolyticus strains produced urease and they could not tolerate 10% O2. They also failed to be agglutinated in a hyperimmune serum raised against T. equigenitalis; however, B. ureolyticus and T. equige...
Varadin M.Infertility, resulting from failure to conceive during the preceding breeding season, was caused by various forms of endometritis in forty-four mares of Highland and Arabian breeds in Yugoslavia. Chronic mucopurulent and latent catarrhal endometritis occurred most frequently. Douching of the uterus on alternate days for 9 days with warm and cold sterile salt solutions (ranging from 7% to 1% w/v) in the early autumn resulted in conception in 47-7% of mares at an average of 15-2 days after the onset of treatment, and another 36-7% becoming pregnant in the following spring. Mating at the wrong st...
Stock KF, Distl O.Studbook inspection (SBI) data of 20 768 German Warmblood mares and radiography results (RR) data of 5102 Hanoverian Warmblood horses were used for genetic correlation analyses. The scores on a scale from 0 to 10 were given for conformation and basic quality of gaits, resulting in 14 SBI traits which were used for the correlation analyses. The radiographic findings considered included osseous fragments in fetlock (OFF) and hock joints (OFH), deforming arthropathy in hock joints (DAH) and distinct radiographic findings in the navicular bones (DNB) which were analyzed as binary traits, and radio...
Rossini JB, Rodriguez J, Bresnahan DR, Stokes JE, Carnevale EM.The clinical use of intracytoplasmic sperm injection (ICSI) in horses usually involves the transfer of embryos into recipient mares, resulting in substantial cost increases. This is essential when subfertile mares are oocyte donors; but some donors are fertile, with ICSI compensating for limited or poor-quality spermatozoa. Fertile oocyte donors could carry pregnancies, eliminating the need for a recipient. We assessed the potential of using oocyte donors as recipients for their own ICSI-produced embryos during the same cycle. Donors in oestrus and with large dominant follicles were administer...
Vandeplassche M.The author reviews 40 years of clinical experience including more than 1000 cases of dystocia in mares of different breeds. The high incidence of stillbirth and perinatal mortality of the foal, severe lesions of the genital tract developing during foaling and in the early post partum period are discussed and suggestions made for their prevention and treatment. The advantages of partial embryotomy to avoid unnecessary caesarean sections are emphasised. Special attention is given to the causes of and approach to cases of prolonged gestation; to dystocia caused by retroversion of preparturient to...
Gronwall R, Brown MP.Para-aminohippuric acid (PAHA, 0.1 mg/min/kg of body weight) was infused IV into 2 mares, followed by concurrent IV infusion of PAHA and probenecid (0.075, 0.15, 0.25, or 0.35 mg of probenecid/min/kg). Probenecid infusion reduced the clearance of PAHA at serum probenecid concentrations greater than 55 micrograms/ml. At 12-hour intervals, probenecid (in 5 repeated doses - 50, 75, 100, or 200 mg/kg) was administered by gavage to 2 mares. Mean serum probenecid concentration was greater than 55 micrograms/ml for all dosages. At dosages less than 200 mg/kg, accumulation of probenecid in the serum w...
Thomson P, Pareja J, Núñez A, Santibáñez R, Castro R.Culture-independent techniques have made it possible to expand the knowledge about the composition of bacterial communities present in the healthy uterus and their role in health and disease, mainly in humans. However, in animals like mares, there is a dearth of information regarding this area. To narrow this knowledge gap, the objective of this study was to identify and characterize the composition and function of the uterine microbiome of a group of Chilean purebred mares (CPM), an equine breed with the oldest genealogical record in South America and an economical important reproductive indu...
Leal GR, Monteiro CAS, Carvalheira LR, Souza-Fabjan JMG.Simulated Physiological Oocyte Maturation (SPOM) mimics in vitro the physiological events of oocyte maturation. The system uses cAMP modulators in two steps (pre IVM and IVM) and has presented promising results that are arousing the curiosity of IVF programs in different animal species, generating several papers, adaptations, and controversies worldwide. This study systematically analyses the data in the literature on the use of SPOM and compares the outcomes to the original paper (Albuz et al. Hum. Rep., 25: 2999-3011 2010), classifying them into success or failure. The PubMed, Scopus, and ...
Silvia PJ, Squires EL, Nett TM.Four groups of mares, representing anestrus (AN; n = 8), early transition (ET; n = 7), late transition (LT; n = 8) and estrus (EST; n = 12) were used to examine release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) after a bolus injection of gonadotropin releasing hormone (GnRH) during the transition from anestrus into the breeding season. Estrous mares received GnRH on d 2 or 3 of estrus in the cycle immediately preceding slaughter. Anestrous, ET and LT mares received GnRH exactly 1 wk prior to slaughter. A single injection of GnRH (Sigma LHRH, L-0507, 2.0 micrograms/kg b...
Iuliano MF, Squires EL, Cook VM.A 2 X 2 cross-classified experiment was conducted to investigate the effect of age of equine embryo (7 vs 8 d postovulation) and method of transfer (surgical vs nonsurgical) on pregnancy rates at 50 d of gestation. Embryos were recovered 7 or 8 d postovulation using a Foley catheter and 3 liters of modified Dulbecco's phosphate-buffered saline (PBS). Upon identification, the embryos were placed in millipore-filtered PBS containing 20% heat-inactivated steer serum and maintained at room temperature until transferred. At the time of recovery, embryos were randomly assigned to be transferred eith...
Dutta SK, Campbell DL.Blastic transformation of peripheral blood mononuclear cells and serum neutralization antibody levels for equine herpesivurs type 1 were measured in 19 mares from three farms at the time of termination of their pregnancy by normal foaling or viral abortion. The stimulation indexes of lymphocytes obtained from the mares from two farms (Farm 1 and 2) which had virus abortions, ranged from 2.1 to 10.8. But there was no significant difference in stimulation index levels between the aborting and normal foaling mares on these two farms. Equine herpesvirus type 1 was isolated from the mononuclear cel...
Anaya G, Fernández ME, Valera M, Molina A, Azcona F, Azor P, Solé M, Moreno-Millán M, Demyda-Peyrás S.Twin foaling is associated with chimaerism in several domestic species and is recognised in horses. In this study, 21,097 purebred Spanish (Pura Raza Español) horse births from the 2015 to 2016 breeding season were investigated for chimaerism. Twin foaled and chimaeric individuals were assessed on the basis of foaling records, short-tandem repeat (STR) parentage test results and a sex-linked STR-based technique. Fourteen twin pregnancies with 23 twin foals born alive were identified (0.066% twin foaling prevalence), including five blood chimaeric cases (21.7%; overall prevalence 0.011%), sugg...
Martin KL, Hoffman RM, Kronfeld DS, Ley WB, Warnick LD.Changes in serum concentrations of Ca and parathyroid hormone (PTH) may develop in periparturient mares, may be influenced by dietary Ca, and may be associated with changes in Ca concentration of mammary secretion. Milk and blood samples were taken from eight mares on Farm A and eight on Farm B for 10 d before parturition and from four mares on each farm for 5 d postpartum. Milk Ca was measured by two commercial tests. Serum samples were analyzed for PTH and total Ca in 16 mares and for ionized Ca in six (Farm A). Parturition was induced in eight mares on Farm A and four on Farm B; no signific...
Kenney RM, Ganjam VK, Cooper WL, Lauderdale JW.Seventy-three Standardbred and Thoroughbred mares in clinical anoestrus during the breeding season were treated with PGF2alpha. The mares were divided into four categories; foaling, barren, maiden and unknown. The response was consistent in all groups. Mares at Days 2 to 4 of dioestrus showed no decrease in plasma progesterone levels, and those at Days 6 to 8 showed a return of progesterone to baseline levels (less than 1 ng/ml) in 24 to 48 hr after treatment. Plasma progesterone levels returned to basal levels in 24 to 48 hr in 93% of mares; progesterone levels had not changed by 96 hr in 7% ...
Krohn J, Ennen S, Hospes R, Nieth J, Wehrend A.An effective long-term treatment is necessary for mares with pyometra, because the condition tends to recur. In many affected animals, several conformational or anatomical anomalies contribute to impaired uterine clearance. Ovariohysterectomy is the surgical procedure of choice. Conservative therapy consists of draining and flushing the uterus, and systemic anti-inflammatory and antimicrobial treatment. Uterine secretions tend to accumulate again after local treatment, especially in mares with poor vaginal conformation or cervical adhesions. Herein, we describe three cases in which a cervical ...
Mantovani R, Sartori C, Pigozzi G.This study investigated some aspects of breeding management in the Italian Heavy Draught Horse breed, aiming at improving its efficiency at stud farm level. A first aim was to evaluate the risk of unsuccessful reproduction in mares after an early (3 years) or normal (4 years) age at first foaling, in interaction with different stud rearing systems. A second objective was the examination of the mean time length in which young 2-year-old stallions maintain a genetic superiority on older proven stallions, identifying a 'genetic lifespan' in which young stallions can be safely used for reducing th...
