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.
Navarrete F, Saravia F, Cisterna G, Rojas F, Silva PP, Rodríguez-Alvarez L, Rojas D, Cabezas J, Mançanares ACF, Castro FO.Horse mesenchymal stem cells (MSC) are potential anti-inflammatory tools for post-breeding induced endometritis (PBIE). In this research MSCs isolated from the endometrium or subcutaneous fat of the same donors were infused iu into mares with PBIE for assessment of their anti-inflammatory action and engraftment. PBIE was induced in nine gynecologically healthy mares by iu infusion of 500 million dead sperm in saline. Inflammatory markers were analyzed in uterine lavages and biopsies immediately before (phase I) and 3 h after infusion of sperm (phase II). Measurements: polymorph nuclear cells ...
Renaudin CD, Kelleman AA, Keel K, McCracken JL, Ball BA, Ferris RA, McCue PM, Dujovne G, Conley AJ.Granulosa cell tumours (GCT) are the most common ovarian tumours in mares. While the classical presentation may not represent diagnostic challenges, diagnosis is not easy in the early stages. Objective: Illustrate the variability in the presentation and serum biomarkers associated with ovarian abnormalities in the mare. Methods: Retrospective case series. Methods: Nonclassical cases of GCTs and other ovarian conditions were identified and behaviour, GCT endocrine results, palpation and ultrasonographic findings are described and the diagnostic value of each is discussed. Results: Mares in this...
Kaps M, Okada CTC, Gautier C, Aurich J, Scarlet D, Kuhl J, Aurich C.Behavior during the estrous cycle of mares can affect their performance and therefore inhibition of cyclical ovarian activity is indicated. We hypothesized that implants containing the GnRH analog deslorelin downregulate GnRH receptors and inhibit ovulation in mares. The estrous cycles of Shetland mares were synchronized with 2 injections of a PGF analog. One day after the second injection (day 0), mares received 9.4 (group D1, n = 6) and 4.7 mg deslorelin (D2, n = 5) as slow-release implants or 1.25 mg short-acting deslorelin as a control (C, n = 5). Ultrasonography of the reproductive trac...
Larentis GR, Bastos HBA, Centeno LAM, Bueno VC, Bringel BA, Mattos RC.The present case report aimed to determine the responsiveness of the endometrium and the ovaries of an X0 mare after hormonal treatment. On transrectal palpation, the uterus was flaccid and smaller than normal, and the ovaries were small and smooth. The endometrium had normal histological architecture, with an atrophic glandular epithelium. A karyotype evaluation was performed, and 70 cells presented 63 chromosomes, lacking one sex chromosome. Circulating hormonal levels of total estrogens were 43.93 pg/mL; progesterone 0.01 ng/mL; testosterone 48 pg/mL; FSH 30.3 ng/mL; and LH 1.71 ng/mL. ...
Watson E, Davis A, Splan R, Porr CAS.With increasing public scrutiny on animal welfare, it behooves those involved in the equine industry to revisit best management practices to ensure these support healthy horses. There is little published research on how horses are used in the equine industry, particularly in therapeutic horseback riding (THR) programs. Although there is a large amount of information on the benefits of THR programs to the participants, there is little published information available about the horses. Therefore, the objective of this survey was to gather data regarding horse use and care in Professional Associat...
EHV1 and EHV4 are the most important herpesviruses in horses. Repeated cases of abortion in mares regularly vaccinated, prompted us to investigate the immune response after vaccination with the same inactivated vaccine, but with three different protocols. Eighteen mares were chosen and randomly divided in three study groups (G-G-G) and a control group (Ctrl). For serologic and PCR investigations nasal swabs, sera and blood were collected. The protocol used in G (4 doses) increased the titer recorded by ELISA and seroneutralization (SN). Poor agreement and no correlation were observed in titer ...
Wilsher S, Bowker A, Silva J, Allen WRT.A total of 127 normal placentas from Arabian mares resident in the United Arab Emirates were examined. The mean linear dimensions of the placenta were, on average, 84% of those previously recorded for the placentas of the Thoroughbred. Significant differences in the size of the allantochorion between primigravid and multiparous mares were seen only in the linear dimensions of the body portion. The pregnant horn was more commonly on the right than left side of the uterus (P = .01; 74/127; 58%). Cord attachment was primarily at the base of the two placental horns (112/127; 88%), with the remain...
Dos Reis WVA, de Braga D, Júnior MV, Gheller JM, de Deco-Souza T, da Costa E Silva EV, Sampaio BFB, Macedo GG.Dispersed ovulation at the breeding (BS) and anestrus at non-breeding season (NBS) are major impediments to embryo transfer and insemination programmes. The present study aimed to evaluate a hormonal P4/E2-based synchronisation protocol in mares during both the BS and the NBS on ovarian/follicle behaviour. Mares underwent a hormone protocol to synchronise their ovulation during the BS (n = 8) and NBS (n = 10), starting (D0) with the insertion of an intravaginal device containing 1 g of P4 and 7 mg Estradiol Benzoate IM. (EB). On D9, the device was removed and injected with 0.25 mg o...
Santos-Jimenez Z, Martinez-Herrero C, Encinas T, Martinez-Ros P, Gonzalez-Bulnes A.The present study compared the occurrence of oestrus behaviour and ovulation in response to the insertion of CIDR devices plus a classical treatment with equine chorionic gonadotrophin (eCG; single dose at CIDR removal) or alternative treatments with gonadotrophin-releasing hormone (GnRH, either in a single dose at 56 hr after CIDR removal, or in one dose at CIDR insertion and another dose at 56 hr after CIDR removal). The appearance of oestrus behaviour during reproductive season ranged between 84% and 95% and all females showing oestrus signs had subsequent ovulations. The response, during...
Marcos R, Ribeiro T, Santos M, Correia-Gomes C, Macedo S, Guimarães T, Blielbernicht M, Caniatti M, Rocha A.Uterine lavage (UL) is a routine diagnostic procedure for endometritis. In UL the fluid is centrifuged and the sediment smeared. Samples prepared in cytocentrifuges, the so-called "cytospins", are useful for evaluating cells in fluids, but never been used in UL. The aim of this study was to assess the usefulness of cytospins after UL, comparing automatic versus manual cytocentrifuges, and to determine their value for the diagnosis of endometritis. The study was divided in two parts. Firstly, UL was performed in 16 mares and a small part of the retrieved fluid was cytocentrifuged in an automati...
Fernández-Hernández P, Sánchez-Calabuig MJ, García-Marín LJ, Bragado MJ, Gutiérrez-Adán A, Millet Ó, Bruzzone C, González-Fernández L....Production of equine embryos in vitro is currently a commercial technique and a reliable way of obtaining offspring. In order to produce those embryos, immature oocytes are retrieved from postmortem ovaries or live mares by ovum pick-up (OPU), matured in vitro (IVM), fertilized by intracytoplasmic sperm injection (ICSI), and cultured until day 8-10 of development. However, at best, roughly 10% of the oocytes matured in vitro and followed by ICSI end up in successful pregnancy and foaling, and this could be due to suboptimal IVM conditions. Hence, in the present work, we aimed to elucidate the ...
Jones CJP, Aplin JD, Allen WRT, Wilsher S.From Day 6.5-7 post-conception until its loss around Day 22, the equine embryo is enclosed in a mucinous capsule that prevents direct intercellular interaction between the trophectoderm and uterine epithelium. The embryo is, however, bathed in glycoprotein-rich secretions. In this study, lectin histochemistry was used to characterise the distribution and glycan composition of uterine glycoproteins destined for secretion, and to ascertain the local effect of an embryo on glycosylation in the endometrium. Endometrial biopsies were taken from mares in estrus, on Days 5, 8, 12 and 15 of diestrus, ...
Little SV, Hillhouse AE, Lawhon SD.This is a report of two Bacillus safensis genomes sequenced from separate cultures isolated from the uterus of a 16-year-old Westphalian mare that aborted a dead fetus. This strain represents the first case of a B. safensis-associated equine abortion and the first case of infection caused by this bacterium.
Szóstek-Mioduchowska AZ, Baclawska A, Rebordão MR, Ferreira-Dias G, Skarzynski DJ.An increasing number of studies have shown that prostaglandins (PGs) exert multiple regulatory actions in the processes associated to tissue remodeling and fibrosis. Extracellular matrix (ECM) turnover is mediated by matrix metallopeptidases (MMPs). The knowledge about the regulation of their expression in mare endometrium is still limited. Thus, the aim of this study was to investigate whether: (i) profibrotic transforming growth factor (TGF)-β1 modulates PG production in equine endometrium; and (ii) PGE and PGF modulate MMPs, their tissue inhibitors (TIMPs), and collagen 1 (COL1) expression...
Novello G, Podico G, Segabinazzi LGTM, Lima FS, Canisso IF.The objective of this study was to compare semen parameters and embryo recovery rates of cooled stallion semen extended with INRA 96 or BotuSemen Gold. In experiment 1, 45 ejaculates from nine mature stallions were collected, assessed, and equally split between both extenders and then extended to 50 million sperm/mL. Then, the extended semen was stored in three passive cooling containers (Equitainer, Equine Express II, and BotuFlex) for 48 hours. In experiment 2, the same ejaculates extended in experiment 1 were cushion-centrifuged, the supernatant was discarded, and the pellets were resuspend...
Gáspárdy A, Renkó E, Somoskői B, Bába A, Cseh S.The objective of this study was to compare the efficiency of artificial insemination (AI) carried out with frozen and fresh, diluted and chilled semen under field conditions. One hundred and twenty-nine mares of different breeds were included in the study. Eighty-one out of the 107 mares inseminated with fresh, chilled semen got pregnant. Seven pregnant mares aborted and 74 foals were born. Out of the 22 mares inseminated with frozen semen, 17 mares got pregnant. Two mares out of the 17 pregnant mares aborted and finally 15 healthy foals were born. No difference was found between the two group...
Satué K, Montesinos P, Muñoz A.In women and females of different species of laboratory animals, oestrogens stimulate the renin-angiotensin-aldosterone system (RAAS) by increasing tissue and circulating levels of angiotensinogen and renin during the preovulatory period. Progesterone and cortisol compete with aldosterone for mineralocorticoid receptors, which results in increased Na+ reabsorption during the postovulatory period. The purpose of the current research was to analyse the relationship of oestradiol-17β, progesterone and cortisol with RAAS in 23 mares during an oestrous cycle. During the preovulatory period, signif...
Cuervo-Arango J, Martín-Peláez MS, Claes AN.The echogenicity of the early CL undergoes obvious changes during the first 5 days of luteal development. This phenomenon could potentially be used to estimate the age of the CL in mares which have not been checked frequently for the diagnosis of ovulation. The objective of this retrospective study was to determine the accuracy of estimating the age of the early CL (Day 0 to Day 4; Day 0 = Day of ovulation) in recipient mares examined for the first time in the breeding season to be used in a commercial embryo transfer (ET) program. The post-transfer pregnancy rate and embryo loss of 28 recip...
Piotrowska-Tomala KK, Jonczyk AW, Skarzynski DJ, Szóstek-Mioduchowska AZ.Prostaglandins (PGs) play crucial roles in the regulation of the oestrus cycle and establishment of pregnancy in animals. Luteinizing hormone (LH) and ovarian steroids are involved in regulating endometrial PG production in many species. Their effects on PG production and associated pathways in the mare myometrium and endometrium are the subjects of our interest. This study aimed to evaluate the specific effects of LH and ovarian steroids on equine myometrial and endometrial tissues on (i) PGE and PGF secretion and (ii) transcription of genes encoding specific enzymes responsible for PG synthe...
Sharifzadeh A, Shokri H.Due to the limited range of antifungals available to treat genital Candida infections and the emergence of resistant isolates, attention has focused on the antifungal potency of natural compounds with promising biological properties. Objective: To examine whether eugenol synergises the in vitro efficacy of voriconazole against Candida strains isolated from the genital tract of mares. Methods: In vitro experiment. Methods: The antifungal activity of eugenol and voriconazole was evaluated using the broth microdilution assay (CLSI- M27-A3). Synergism of eugenol and voriconazole against genital Ca...
Palmer E, Chavatte-Palmer P.Reproductive technologies aim at improving fertility with the ultimate result of improving genetic selection. In equidae, the respective contribution of different methods of horse management and breeding to genetic progress remain difficult to evaluate as breeding strategies affect the number of offspring per mare or stallion whereas different selection methods (based on pedigree, performance, genomics or progeny's performance) will be applicable at different ages, leading to different accuracy in the estimation of the breeding value. Here, a mathematical model was applied to evaluate theoreti...
Müller V, Toribio RE, Dembek K, Moraes BSS, Mousquer MA, Curcio BR, Nogueira CEW.There are few publications on occurrence of nonthyroidal illness syndrome in foals and on the prognostic value of cortisol and thyroid hormone (TH) concentrations in newborn foals. Objective: To determine serum cortisol and TH concentrations (total and free thyroxine: T and T ; total and free triiodothyronine: T and T ) in foals born from mares with placentitis, to determine their association with survival, and their use as prognostic markers. Methods: A cohort of 29 newborn foals comprising 5 Control, 14 Low-risk, and 10 Sick foals were evaluated over the first week of life. Methods: In thi...
Data in briefApril 25, 2020
Volume 30 105616 doi: 10.1016/j.dib.2020.105616
Nieto-Olmedo P, Gaitskell-Phillips G, Martín-Cano FE, Ortiz-Rodríguez JM, Peña FJ, Ortega-Ferrusola C.This article provides the dataset for the use of power Doppler ultrasound to assess the equine uterus from the recent research article titled "Power Doppler can detect the presence of 7-8 days conceptuses prior to flushing in an equine embryo transfer program"(1). The vascularization of the endometrium was objectively assessed in mares by quantification of pixels in bitmap format (BMP) using computer assisted analysis of images. Fifty-two mares were examined on days 7 (26 mares) and 8 (26 mares) post-ovulation prior to performing flushing procedures for embryo recovery. Receiver operating char...
Lopez-Rodriguez MF, Cymbaluk N, Epp T, Laarveld B, Serrano Recalde EC, Simko E, Card C.Exposure to plants containing glucosinolates (GSLs) affects thyroid function in many species, in horses is implicated in the birth of foals with congenital hypothyroidism. The present study was performed to determine the effect of feeding a GSL (sinigrin) in combination with a low-iodine diet for 12 weeks on thyroid hormones and serum iodine concentrations in nonpregnant mares. Nineteen mares aged 2-14 years were divided into control (n = 6), low (20 mmol/day) (n = 7) and high GSL (35 mmol/day) (n = 6) groups. Thyrotropin-releasing hormone (TRH) stimulation tests and serum iodine measur...
Sampaio BFB, DeRossi R, Vieira N, Milan B, Ávila LG.The objective of the study was to compare the effects of caudal epidural bupivacaine and dexmedetomidine (DEX) combination, with bupivacaine or DEX plain for perineal analgesia in mares. Six healthy saddle mares weighing 330-370 kg and aged 10-15 years were used in this study. Each mare was assigned to receive three treatments: 0.04 mg/kg 0.25% bupivacaine (BP), 2 μg/kg DEX (DX), or 0.02 mg/kg bupivacaine and 1 μg/kg DEX (BPDX). The order of treatments was randomized. All drugs were injected into the caudal epidural space (Co1-Co2) through a 16-G Tuohy epidural needle. After the epidur...
Lazzari G, Colleoni S, Crotti G, Turini P, Fiorini G, Barandalla M, Landriscina L, Dolci G, Benedetti M, Duchi R, Galli C.Assisted reproduction technologies (ART) are well developed in humans and cattle and are gaining momentum also in the equine industry because of the fact that the mare does not respond to superovulation but can donate large numbers of oocytes through ovum pick up (OPU). After collection, the oocytes can be fertilized by intracytoplasmic sperm injection (ICSI) using a variety of stallion semen samples, even of poor quality, and the resulting embryos can establish high pregnancy rates after cryopreservation and transfer. The discoveries that equine oocytes can be held at room temperature without...
Linhares Boakari Y, El-Sheikh Ali H, Dini P, Loux S, Barbosa Fernandes C, Esteller-Vico A, Scoggin K, Lawrence L, Ball B.An intravenous large dose of protein led to an increased blood urea nitrogen (BUN), resulting in a lesser uterine pH and altered uterine gene expression in mares. The objective of the present study was to evaluate effects of a more physiological methodology to increase BUN on the endometrium of mares. Mares were fed hay and a treatment or control diet (n = 11 mares/treatment) in a crossover design starting at time of ovulation detection (D0) and continuing until D7. Mares of the treated group were fed urea (0.4 g/kg BW) with sweet feed and molasses, and those of the control group were fe...
Fedorka CE, Murase H, Loux SC, Loynachan AT, Walker OF, Squires EL, Ball BA, Troedsson MHT.Maintaining yearly foal production is important for the economic success of the broodmare, and this requires breeding to occur as quickly postpartum as possible. The initial postpartum estrus occurs within 5-20 days postpartum, whereas the uterus is still undergoing repair from tissue alterations during pregnancy and parturition, a process known as involution. Attempts have been made to hasten this process, but with minimal success. Mycobacterium cell wall fraction (MCWF) is an immunomodulator that has been shown to reduce bacterial growth and alter aspects of the immune response to breeding,...
Ferreira CSC, Morais RCL, de Andrade ABP, Balaro MFA, Ribas JAS, Gomes GM, Pinna AE.The aim of this study was to evaluate whether the RI and PI values would help in choosing the best embryo recipient, and observe whether CL vascularization would influence P4 production. During the breeding season 2018/2019, the study was conducted using 35 mares, which is used for reference to collect data for the project on the day of embryo transfer. The utilized mares were divided into five groups followed by the day after ovulation, with D0 being the day of ovulation. Therefore, the five groups are as follows: D4-mares that were on the 4th post-ovulation day; D5-mares that were on the 5th...
Donadeu FX, Pedersen HG.The mare provides a unique experimental model for studying follicle development in monovular species. Development of antral follicles in horses is characterized by the periodic growth of follicular waves which often involve the selection of a single dominant follicle. If properly stimulated, the dominant follicle will complete development and eventually ovulate a fertile oocyte. Regulation of follicular wave emergence and follicle selection involves an interplay between circulating gonadotropins and follicular factors that ensures that individual follicles are properly stimulated to grow (or t...
Janczarek I, Stachurska A, Wilk I, Krakowski L, Przetacznik M, Zastrzeżyńska M, Kuna-Broniowska I.Touching the skin by gentle stroking is frequently used to reward horses. The objective of the study was to examine emotional excitability and behaviour of horses in response to stroking different regions of their bodies. The study included 15 adult warmbloods and 15 adult ponies, nine geldings and six mares within each type of horse. First, a novel-object test was conducted. For five successive days, one of five regions of the horse's body was stroked on each side for 5 min. Heart rate and heart rate variability were monitored at rest, during the test and stroking. Simultaneously, horse beha...
Norton JL, Dallap BL, Johnston JK, Palmer JE, Sertich PL, Boston R, Wilkins PA.The period between the onset of dystocia and its resolution has an important bearing on fetal outcome. There are few published data on which to base decisions regarding optimum management of cases in practice. Objective: To evaluate and compare the effects of a coordinated dystocia management protocol (CDMP) with that of a previous protocol of random management on time to resolution and outcome in both an emergency dystocia referral population of mares (referred emergency cases: EM) and in a population of mares residing in hospital due to high risk pregnancy (HRP) concerns that then experience...
Causey RC.Uterine infections are a major cause of infertility, but the role of mucus in equine uterine defense is not well understood. Mucociliary currents play an important role in protecting mucous membranes, including the upper and lower respiratory tracts of mammals, and are required for feeding and oxygenation of many aquatic invertebrates. Although phagocytosis has long been considered the first line of uterine defense in the mare, there are concerns about its efficacy in the uterine lumen. Additional local defenses, such as mucociliary currents, have therefore been proposed. The uterine epitheliu...
Burger D, Dolivo G, Marti E, Sieme H, Wedekind C.Odours of vertebrates often contain information about the major histocompatibility complex (MHC), and are used in kin recognition, mate choice or female investment in pregnancy. It is, however, still unclear whether MHC-linked signals can also affect male reproductive strategies. We used horses (Equus caballus) to study this question under experimental conditions. Twelve stallions were individually exposed either to an unfamiliar MHC-similar mare and then to an unfamiliar MHC-dissimilar mare, or vice versa. Each exposure lasted over a period of four weeks. Peripheral blood testosterone levels ...
Adams AP, Oriol JG, Campbell RE, Oppenheim YC, Allen WR, Antczak DF.This research tested the hypothesis that immunological sensitization of mares by skin allografting, followed by the establishment of pregnancy using semen from the skin-graft donor, would give rise to secondary immune responses to the developing horse conceptus, resulting in an earlier demise of the fetally derived endometrial cups. Maiden mares received skin allografts from a stallion homozygous for Major Histocompatibility Complex (MHC) antigens and/or equivalent autografts and were subsequently mated to the skin-graft donor stallion during the next two breeding seasons. Mares that had been ...
Rodgerson DH, Belknap JK, Wilson DA.To describe in horses and ponies a laparoscopic ovariectomy technique facilitated by electrosurgical instrumentation. Methods: Elective ovariectomy was performed in 23 mares using laparoscopic electrosurgical instrumentation. Methods: Twenty-three mares (13 horses, 10 ponies), aged from 2 to 21 years and weighing 90 to 545 kg. Methods: Food was withheld for a minimum of 12 hours. Mares were sedated with detomidine hydrochloride (0.02 to 0.03 mg/kg) or xylazine hydrochloride (0.5 to 1.0 mg/kg). Excluding the pony mares, all other mares were restrained in stocks. Portal sites in the paralumbar f...
de Andrade AF, Zaffalon FG, Celeghini EC, Nascimento J, Tarragó OF, Martins SM, Alonso MA, Arruda RP.Effect of seminal plasma addition after thawing on viability or cryocapacitation is not definitively established. This experiment was performed to verify the effect of adding seminal plasma, autologous or homologous (from an animal with good semen freezability). Five ejaculates from each of four stallions with proven fertility were collected and cryopreserved. The semen was subsequently thawed and divided into the following three treatment groups: no seminal plasma addition after semen thawing (NOSP); the addition of homologous seminal plasma after semen thawing (HSP) and the addition of autol...
Ginther OJ.Prolonged luteal activity is one of the most formidable terminology challenges in mare reproductive biology. Prolonged luteal activity can be a result of persistence of an individual corpus luteum or the sequential development of luteal glands, each of which may have a normal life span. Luteal tissue can originate from an unovulated follicle or from an ovulation occurring during either follicular or luteal dominance. These complexities, together with ambiguous and inconsistent terminology, have resulted in confusion regarding those conditions which can be grouped broadly under the term prolong...
Taira T, Fujinaga T, Okumura M, Yamashita K, Tsunoda N, Mizuno S.Haptoglobin (Hp) was isolated from equine serum by ammonium sulphate precipitation, anion-exchange chromatography and gel filtration. Equine Hp which migrated to the alpha 2-globulin region in electrophoresis, contained 2 fractions with molecular weights (NW) of 108,000 and 105,000, and each fraction consisting of 2 subunits. Quantitative measurement of Hp in equine serum was performed by the single radial immunodiffusion method using anti-equine Hp serum. In clinically normal horses, the highest concentration of serum Hp was found in newborn foals and a high value was maintained until 12 mont...
Donadeu FX, Watson ED.The annual reproductive cycle in the horse involves a reduction in ovarian activity during short days. The absence of ovulatory activity during winter has important consequences for an equine industry eager to breed mares early during the year. The anovulatory season results from a reduction in the secretion of pituitary gonadotropin that is in turn triggered by the inhibitory effects of short photoperiod on the hypothalamus-pituitary axis. Recent studies have provided evidence that the response of the ovaries to endocrine stimuli during the anovulatory season is affected not only by circulati...
East LM, Dargatz DA, Traub-Dargatz JL, Savage CJ.Enterocolitis associated with Clostridium perfringens (C. perfringens) infection in neonatal foals is often severe and has been associated with a high case-mortality risk. We designed a premises-based survey to evaluate the associations of regional foaling practices, premises environmental management, periparturient foal and brood-mare management, and periparturient brood-mare ration with the occurrence of neonatal enterocolitis attributed to C. perfringens infection. Potential risk factors individually associated with enterocolitis were breed type, housing type at foaling and in the first thr...
Sikora M, Król J, Nowak M, Stefaniak T, Aubertsson G, Kozdrowski R.Endometritis is a common problem in a broodmare practice, often leading to infertility. The diagnosis is based on several methods such as cytology, bacteriology and histopathology; however the outcome of these methods may be inconclusive even when used together. The objectives of this study were: (1) to investigate the usefulness of acute phase proteins as an additional diagnostic tool for diagnosis of subclinical endometritis in mares and (2) to evaluate the association between macroscopic changes in uterine flushes and inflammation of the uterus. Materials were collected from 53 Icelandic ma...
The Journal of physiologyNovember 1, 1974
Volume 242, Issue 3 805-826 doi: 10.1113/jphysiol.1974.sp010735
Comline RS, Silver M.1. Blood gas tensions, pH, PCV, O(2) affinity and red cell 2,3-diphosphoglycerate (DPG) levels have been measured in uterine and umbilical blood in conscious cows and mares with indwelling vascular catheters and in sows under sodium pentobarbitone anaesthesia.2. Large P(O2) gradients (20-24 mmHg) were observed between the uterine and umbilical venous blood in the cow and pig, while in the mare the corresponding P(O2) difference was only 2.7 +/- 1.7 mmHg. Alterations in maternal arterial P(O2) did not affect the large vein-to-vein P(O2) difference in either ruminant or pig.3. In the cow the pre...
Rasch K, Schoon HA, Sieme H, Klug E.The aim of this field study was to examine the influence of the uterotonic substance oxytocin in 2 different therapeutic dosages of 15 and 25 i.u., respectively on the uterine drainage of oestrous mares and on their fertility. In addition endometrial biopsies of mares with and without intrauterine fluid accumulations around the time of ovulation were evaluated histomorphologically regarding the aetiology of susceptibility to uterine infection. A population of 59 Hanoverian Warmblood mares was used in this study. The mares were divided into Group A (mares with intrauterine fluid accumulations [...
Kozdrowski R, Sikora M, Buczkowska J, Nowak M, Raś A, Dzięcioł M.The aim of this study was to ascertain if (1) the stage of reproductive cycle influences cytological results, (2) cytology obtained from an endometrial biopsy is more accurate than cytology derived using the cytobrush, and (3) different methods used for evaluation of cytological samples produce similar diagnostic results. Material was collected from 46 mares in estrus, 48 in diestrus and from 33 mares in anestrus. Smears were evaluated using two criteria. In criterion I, a total of 300cells were counted and the percentage of polymorphonuclear cells was recorded. In criterion II, the number of ...
Bailey CS, Heitzman JM, Buchanan CN, Bare CA, Sper RB, Borst LB, Macpherson M, Archibald K, Whitacre M.Early, accurate diagnosis of ascending placentitis in mares remains a key challenge for successful treatment of the disease. Doppler ultrasonography has shown promise as a tool to diagnose pregnancy abnormalities and is becoming more available to equine clinicians. However, to date, no studies have prospectively compared this technique to standard B-mode measurement of the combined thickness of the uterus and placenta (CTUP). Objective: The objective of the current study was to compare Doppler and B-mode ultrasonography for the detection of experimentally-induced ascending placentitis in mares...
Scholtz EL, Krishnan S, Ball BA, Corbin CJ, Moeller BC, Stanley SD, McDowell KJ, Hughes AL, McDonnell DP, Conley AJ.One of the most widely accepted axioms of mammalian reproductive biology is that pregnancy requires the (sole) support of progesterone, acting in large measure through nuclear progesterone receptors (PRs) in uterine and cervical tissues, without which pregnancy cannot be established or maintained. However, mares lack detectable progesterone in the latter half of pregnancy. Instead of progesterone, several (mainly 5α-reduced) pregnanes are elevated and have long been speculated to provide progestational support in lieu of progesterone itself. To the authors' knowledge, evidence for the bioacti...
Fowden AL, Mundy L, Ousey JC, McGladdery A, Silver M.Glycogen and glucose 6-phosphatase levels were measured in a variety of tissues from fetal, newborn and adult pregnant mares. Hepatic and renal glucose 6-phosphatase activities increased with increasing gestational age and rose further in the 24 h after birth to values similar to those observed in maternal tissues. The glycogen content of fetal liver and skeletal muscle also increased in late gestation, whereas that of fetal lung and cardiac muscle decreased toward term. No significant change in renal glycogen content with fetal age was observed. The values of hepatic glycogen and glucose 6-ph...
Cudd TA, LeBlanc M, Silver M, Norman W, Madison J, Keller-Wood M, Wood CE.Fetal maturation and the timing of parturition in both sheep and primates are thought to be controlled by the hypothalamic-pituitary-adrenal axis but little is known about the endocrinology of the equine fetus. We investigated the ontogeny of plasma concentrations of adrenocorticotropic hormone (ACTH), cortisol and corticosteroid binding capacity in the late-gestation fetal horse. We also wished to determine whether there is ultradian rhythmic release of ACTH and cortisol in fetal horses and we compared fetuses to maternal and non-pregnant adult horses. Six fetuses, 278-304 days gestation (ter...
Samper JC.The two most common procedures for breeding management of mares involve induction of luteolysis and induction of ovulation. Although both of these events are usually achieved, physiologic conditions affect the timing of the response. In a diestrus mare treated with prostaglandin F(2alpha) (PGF), or a PGF analogue, it is well documented that, on average, the interval from treatment to the onset of estrus is 3-4 days, whereas ovulation occurs 8-10 days after treatment. However, the diameter of the ovulatory follicle, as well as its status at the time of PGF treatment, determines the intervals fr...
Lear TL, Lundquist J, Zent WW, Fishback WD, Clark A.Repeated early embryonic loss (REEL) represents a considerable economic loss to the horse industry. Mares that experience REEL may be overlooked as potential carriers of a chromosome abnormality. Here we report three different autosomal translocations in Thoroughbred mares presented for chromosome analysis because of REEL. The karyotypes were 64,XX,t(1;21), 64,XX,t(16;22), and 64,XX,t(4;13), respectively. In order to confirm the chromosomes involved in the translocations, to map the breakpoints, and to determine if the translocations were reciprocal, genes surrounding the breakpoints were iden...
Virgin J, Hendrickson D, Wallis T, Rao S.To compare the presence or absence of pain, pain-related behavioral responses, and hormonal responses to noxious stimuli during standing laparoscopic ovariectomy in mares sedated with continuous intravenous (IV) detomidine infusion and caudal epidural detomidine. Methods: A double blind prospective study. Methods: Mares (n=12) Methods: Mares were divided into 2 treatment groups; 6 were sedated using continuous IV detomidine infusion and 6 were sedated with caudal epidural detomidine. All mares received IV xylazine (0.33 mg/kg) and butorphanol tartrate (5 mg) premedication before detomidine adm...
Bouré L, Marcoux M, Laverty S.The purposes of this study were to develop a technique of paralumbar fossa laparoscopic ovariectomy using Endoloop ligatures and to avoid a laparotomy incision for ovary removal by using a 33-mm diameter muscle spreader trocar-cannula unit. Methods: Seven mares. Methods: Bilateral laparoscopic ovariectomy was performed under general anesthesia in two horses and under neuroleptanalgesia and local anesthesia in five standing mares. Ovaries were approached from the ipsilateral paralumbar fossa through two portal sites located in the paralumbar fossa and a third between the 17th and 18th ribs. Ins...
Ferreira-Dias G, Botelho M, Zagrajczuk A, Rebordão MR, Galvão AM, Bravo PP, Piotrowska-Tomala K, Szóstek AZ, Wiczkowski W, Piskula M, Fradinho MJ....Phytoestrogens exist in plants that are present in forages fed to horses. They may compete with 17-β estradiol and influence the estrous cycle. Therefore, the objective was to determine whether coumestrol from clover-mixed pastures is present in mare's plasma after their ingestion (experiment I), and when this phytoestrogen was present in mare's plasma after ingestion (experiment II). The effect of a long-term ingestion of phytoestrogens on estrous cycle disruption was assessed (experiment III; clinical case). Experiment I was carried out in nonpregnant anestrous and cyclic Lusitano mares (n ...
Battut I, Colchen S, Fieni F, Tainturier D, Bruyas JF.The purpose of this study was to evaluate the exact age when the equine embryo reaches the uterus. The time of ovulation was determined by hourly ultrasound examinations starting 32 h after an injection of crude equine pituitary gonadotrophin or human chorionic gonadotrophin, or after the first of 4 injections of buserelin. Nonsurgical uterine flushings were carried out 144 h (Day 6), 156 h (Day 6.5) or 168 h (Day 7) after ovulation. Induction of ovulation was attempted in 101 oestrous cycles and 61 of 101 mares (60.4%) ovulated 32-44 h post injection. Sixty embryo collections were performed w...
Pashen RL, Allen WR.The effects of fetal gonadectomy on steroid production and the maintenance of pregnancy in the mare were studied. Removal of the fetal gonads resulted in an immediate fall in maternal plasma concentrations of conjugated and unconjugated oestrogens whereas progestagen levels remained unchanged. Hormone profiles in mares carrying sham-operated fetuses remained similar to those in unoperated control mares. Plasma levels of 13,14-dihydro-15-oxo-PGF-2 alpha (PGFM) were much lower, and uterine contractions weaker, during labour in mares carrying gonadectomized foals than in control mares. Pregnancy ...
Shikichi M, Iwata K, Ito K, Miyakoshi D, Murase H, Sato F, Korosue K, Nagata S, Nambo Y.Measurement of progestines and estrogens in maternal plasma has been advocated as an indicator of foeto-placental function. The goals of the present study were as follows: to determine progestin and estrogen concentrations in mares with normal and abnormal pregnancies during late gestation, evaluate the diagnostic value of hormone concentrations, and investigate the relationship between hormone concentrations after treatment and the survival of foals. Blood samples were collected monthly from 459 pregnant mares between Day 201 of gestation and foaling. Progestin and estrogen concentrations wer...
Rivero JL, Galisteo AM, Agüera E, Miró F.Muscle biopsies were taken from the middle gluteal muscle of 143 untrained horses (83 Andalusians [AN] and 60 Arabians [AR]) ranging from 10 days to 24 years old. The horses were separated according to breed and sex and allotted to five age groups: A, 0 to three months; B, yearlings; C, two to three years; D, five to 10 years; and E, 11 to 24 years. There was an increase in the percentage of type I fibres (about 100 per cent) as well as a decrease in the percentage of type IIB fibres (AN, 50 per cent; AR, 40 per cent) over the five age groups. The percentage of type IIA fibres rose significant...
Bailey CJ, Reid SW, Hodgson DR, Rose RJ.To determine whether sex or foaling period were associated with time to first race start and whether sex, age at time of first race start, or inter-race period were associated with career duration for Thoroughbred racehorses in Australia. Methods: 553 Thoroughbred racehorses. Methods: Race records through to the end of the 6-year-old racing season were obtained for each horse. Product-limit survival analysis was used to determine whether sex or foaling period was associated with time to first race start and whether sex or age at first race was associated with career duration. A Cox proportiona...
